Description of the preimaginal instars and redescription of the adult stage of Belostoma elongatum Montandon (Hemiptera: Belostomatidae) Author Reyes, Cristina Armúa De Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, 9 de julio 1449 (3.400) Corrientes. Argentina. E-mail: acarmua @ exa. unne. edu. ar Museo de La Plata, Universidad Nacional de La Plata. Paseo del Bosque Bosque s / n. (1900) La Plata. Argentina. E-mail: estevezanalia @ hotmail. com Museo de La Plata, Universidad Nacional de La Plata. Paseo del Bosque Bosque s / n. (1900) La Plata. Argentina. E-mail: js @ netverk. com. ar Author Estévez, Na. L. Author Schnack, Juan A. text Zootaxa 2006 2006-04-19 1175 1175 37 42 journal article 1175­5334 4FD4E2D9-5661-43EB-A8AE-6DF3E556298A Belostoma elongatum Montandon Belostoma elongatum Montandon,1908: 299 ; De Carlo, 1938: 214–215; Lauck, 1962: 77–78; Schnack, 1976: 33; Lanzer­de­Souza, 1980: 55–56. Belostoma bosci , De Carlo, 1930: 112 . Redescription of the adult ( Figs. 1–6 ) Size: length: ♂♂ : 35.0–38.0 mm, ♀♀ : 35.5–38.8 mm ; width: ♂♂ 13.5–15.0 mm, ♀♀ : 14.0– 15.8 mm . Shape: body elongate, narrow ( Fig. 1 ). Color: yellowish brown. Structural Characteristics Head: suturae anteclipeus­maxillary plate longer than suturae anteclipeus­lorum; anteoculus as long as interoculus; eyes globose, as wide as long ( Fig. 1 ) beak: segment I longer than segment II ( Fig. 2 ). Thorax: prosternal keel prominent, projecting anterad ( Fig.2 ). Profemur moderately dilated. Abdomen: pilosity covering more than half of laterotergites, slightly narrower between spiracles, well­developed on penultimate segment ( Fig. 3 ); male genitali a with the arms of phallobase bending ventrad, covering lateral margins of the wide ventral diverticulum ( Figs. 4, 5, 6 ). FIGURES 1–16. Belostoma elongatum . 1–6 adult stage:1 body shape; 2 head lateral view; 3 abdominal pilosity; 4–6 male genitalia: 4 ventral, 5 dorsal and 6 lateral views. 7–16 instars: 7 head, dorsal view; 8 head, first instar ventral view; 9 head, first instar, lateral view; 11 head, second instar, ventral view; 13 head, third instar, lateral view. Dorsal view showing body shape and forewing pad development: 10 first instar, 12 second instar, 14 third instar, 15 fourth instar, 16 fifth instar Observations: this species is easily distinguished from its congeners by its characteristic narrow and elongate body shape, strikingly narrowed from the thorax to the head. Type data: the types were cited by Montandon as follows: ” Paraguay : Asunción (Mus. Nat. Hung.), R. Apa (Mus. Zool. Turín) et ma collection”. These specimens probably are deposited at the Hungarian National Museum . Material Examined The adult specimens examined were those reared in the laboratory ( 5 ♂♂ , 6 ♀♀ ) (see Table 1 ), those collected as adults and kept in the laboratory ( 5 ♂♂ , 7 ♀♀ ), and specimens deposited in the (MLP) and (UNNE) The museum specimens bear the following data: Argentina : Chaco : Resistencia 1 ♂ ( MLP ) ; Resistencia 2­XII­1939 , Birabén­Bezzi coll. 1♂ , 5 ♀♀ ( MLP ) ; Tirol. 7­XII­1939 Birabén­Bezzi coll. 1♂ ( MLP ) ; Resistencia 10­II­ 1953 , 1♀ ( MLP ) . Corrientes : Bella Vista , 1♂ ( MLP ) ; Berón de Astrada II­1947 Birabén coll. 1♀ ( MLP ) ; Lag. González 7 ♂♂ , 6 ♀♀ , 15­VIII­ 2004 ( UNNE ) ; Lag. Soto 1♂ , 1♀ , 15­ I­2004 ( UNNE ) ; Saladas 3 ♂♂ , (a la luz) 19­VI­2004 ( UNNE ) . Santa Fe : Reconquista 26­ XI­1939 Birabén­Bezzi coll. 1 ♂ ( MLP ) . Santiago del Estero : Río Salado , Wagner coll. 1 ♀ ( MLP ) . Descriptions of instars ( Figs. 7–16 ) All descriptions except that of the fifth instar were based on the examination of dead specimens and the exuviae of those which molted. First instar. Size: length: 6.0– 7.2 mm ; width: 3.0– 3.6 mm . Shape: body elongate, narrow. Head: anteoculus longer than interoculus; suturae anteclypeus­maxillary plate longer than suturae anteclypeus­lorum; eyes globose ( Fig.7 ), without grooves concealing antennae ( Fig. 8 ). Beak: segment I shorter than II ( Fig. 9 ). Antennae short, one­segmented, exposed, oriented forwards ( Fig. 8 ). Thorax: anterior margin of prothorax concave, posterior margin straight; mesothorax with posterior margin bearing a wide median concavity; wing pads hardly visible on posterior lateral margins of mesothorax.( Fig. 10 ). Prosternal keel pointed, not prominent. Leg I: tarsus one­segmented with two claws, the inner one smaller. Abdomen: dorsum of first segment not reaching lateral margins; respiratory pads reaching posterior margin of second abdominal segment. Material examined: dead nymphs (N: 11); exuviae (N: 24). Second instar: Size: 8.3–9.0 mm; width: 3.9–5.1 mm . Shape: body elongate, narrow. Head: Antennae small, two­segmented, oriented backwards ( Fig. 11 ). Thorax: anterior margin of prothorax with a wide concavity; posterior margin of mesothorax with three projections of same length, one median and two lateral ( Fig. 12 ); prosternal keel sharp­pointed; leg I: internal claw reduced. Abdomen: as in first instar. Material examined: dead larvae (N: 7); exuviae (N: 17). Third instar: Size: length: 9.8–10.7 mm ; width: 5.6–7.3 mm . Shape: body elongate, narrow. Head: with grooves concealing antennae, these three­segmented and with lateral processes Beak: segment I longer than II ( Fig. 13 ). Thorax: anterior margin of prothorax with a less pronounced concavity than in previous instars; mesothorax: forewing pads larger than in previous instar, two deep concavities delimiting a V­shaped medial area, this longer than forewing pads; metathorax: with lateral rounded expansions ( Fig. 14 ). Abdomen: first tergite reaching lateral margins. Material examined: dead larvae (N: 2); exuviae (N: 15). Fourth instar. Size: 11.0 – 12.7 mm ; width 6.8–9.5 mm . Shape: body elongate, narrow. Head: lateral processes of antennae longer than in third instar; grooves housing the antennae deeper than in third instar. Thorax: mesothorax with wing pads larger than in previous instar, V­shaped medial area slightly shorter than forewing pads ( Fig.15 ). Material examined: dead larvae (N: 4); exuviae (N: 11). Fifth instar. Size: 12.7–14.3 mm ; width 9.8–12.0 mm. Shape: body elongate, narrow. Head: antennae with lateral processes longer than in previous instar, fingerlike. Thorax: mesothorax with wing pads reaching second abdominal segment; V­shaped medial area much shorter than wing pads ( Fig. 16 ). Material examined: exuviae (N: 11). TABLE 1 . Dates of recorded events of emergence (E)* and death (D) referred to each stage of development, based upon laboratory rearing from February 2 to June 30, 2001, from the 35 first instars hatched from a B. elongatum male carrying 44 fertilized eggs.

Dates of each recorded event	Larval instars	Adult stage
	L1		L2	L3	L4	L5
February 13	25 (E); 7 (D)	­­	­­	­­	­­	­­
February 14	4 (E)	­­	­­	­­	­­	­­
February 16	6 (E); 4 (D)	­­	­­	­­	­­	­­
February 21	­­	18 (E); 6(D)	­­	­­	­­	­­
February 22	­­	4(E); 1(D)	­­	­­	­­	­­
February 24	­­	2(E)	­­	­­	­­	­­
March 14	­­	­­	12(E); 2 (D)	­­	­­	­­
March 22	­­	­­	3(E)	­­	­­	­­
March 28	­­	­­	2(E)	­­	­­	­­
April 17	­­	­­	­­	10(E); 3(D)	­­	­­
April 26	­­	­­	­­	3(E); 1(D)	­­	­­
April 28	­­	­­	­­	2(E)	­­	­­
May 22	­­	­­	­­	­­	7(E)	­­
May 24	­­	­­	­­	­­	2(E)	­­
May 31	­­	­­	­­	­­	2(E)	­­
June 28	­­	­­	­­	­­	­­	2(E)
June 30	­­	­­	­­	­­	­­	2(E) + 7(E)
Total (E)	35	24	17	15	11	11
Total (D)	11	7	2	4	­	­
# Survivors	24	17	15	11	11	11

Emergence (E) is herein referred as the molt to the instar or stage of development headed at each column (e.g., 25 first instars emerged (hatched) from egg s on February 13; 18 first instars molted to second instars on February 21; etc.)