NO. 3569 



SOLDIER FLY LARVAE — ^McFADDEN 23 



Biology.— Larvae of this species have been collected from leaf axils 

 of cattails only where the axils were above the waterline. 



Material examined. — New York: Ithaca, Apr. 8, 1921, P. W. 

 Claasen and O. A. Johannsen, 5 larvae, 15 puparia collected from leaf 

 axils of cattails, CU; Ithaca, July (?), 2 larvae from leaf axils of 

 cattails, CU. 



Subgenus Sargus Fabricius, 1798 



Key to Species of Subgenus Sargus 



1. Body segments lacking vittae; prothoracic spiracle on stalk like structure. 



elegans Loew 



Body segments with alternating dark and light vittae; prothoracic spiracle 



sessile 2 



2. Dorsal surface of body segments with 3 dark vittae .... decorus Say 

 Dorsal surface of body segments with more than 3 dark vittae 3 



3. Median light band between inner 2 dark vittae parallel sided. 



bipunctatus Scopoli 



Median light band between inner 2 vittae geniculate; each of inner pair of 



setae located in a dark patch in median light band viridis Say 



Sargus (Sargus) elegans Loew, 1866 



Figures 52, 53, 61 



Description. — Mature larva: length 7.8 mm, width 2.4 mm; head 

 not restricted posterior to eye prominence, ratio of width of head at 

 eye prominence to width at neck 1.0. Other characters as given in 

 keys to genera and subgenera, 



Instar no. ?: length 4.5-5.2 mm, mean 4.96 mm; width 1.4-2.0 mm, 

 mean 1.68 mm; differ from mature larvae since they lack the stalked 

 prothoracic spiracle. 



Biology. — Larvae of this species have been collected only from 

 under horse manure. 



Material examined. — Ontario: Marmora, June 19, 1952, J, R. 

 Vockeroth, 2 puparia, larvae collected from under horse dung in 

 woods, CNC. Vu-ginia: Alexandria, June 24, 1951, W. W. Wirth, 

 15 larvae (early instar), from under horse dung, USNM. 



Sargus {Sargus) decorus Say, 1824 



Figures 55, 58, 59 



Description. — Mature larva: length 4.0-4.2 mm, mean 4.1 mm; 

 \\ddth 3.0-3.3 mm, mean 3.13 mm; width of head at eye prominence 

 0.81-0.94 mm, mean 0.87; width of head at neck 0.48-0.59 mm, mean 

 0.52 mm, mean ratio of width of head at eye prominence to width at 

 neck 1.67. Other characters as given in key to species. 



Biology. — Larvae of this species have been collected from rotting 

 leaves and cow manure. 



