22 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 121 



Subfamily Sarginae 



Of the 6 genera listed for this subfamily by James (pers. comm.), 

 larvae have been described for only the following 4 genera: Sargus, 

 Ptecticus, Alicrochrysa, and Merosargus. 



The keys to the genera of this subfamily wiU work for mature 

 larvae only, but, where earlier instars are known, descriptions of 

 these forms are included. 



SuBFAMiLiAL CHARACTERS. — As givcn in key to subfamilies. 



Habitat of larvae. — Larvae of the Sarginae are terrestrial 

 scavengers. They have been collected from various types of manures, 

 rotting vegetation — 'especially garden refuse — and from other types 

 of decaying organic matter. 



Key to Genera of Sarginae 



1. Venter of sixth abdominal segment with sternal patch extending almost the 



length of that segment; venter of fifth abdominal segment with a smaller 



sternal patch (fig. 50) Ptecticus Loew 



Venter of sixth abdominal segment with a shorter sternal patch; sternal patch 

 lacking on venter of fifth abdominal segment 2 



2. Dorsolateral margin of segments 1-10 with a series of large, dark plaques 



arranged in a circular pattern; segments 1-3 with a transverse band of 



these plaques connecting the 2 lateral circles; 5 vittae on dorsum, the mesal 



vitta much broader than the others .... Sargus (Pedicellina) James 



Dorsolateral margin of segments 1-10 lacking markings described above . . 3 



3. Lateral margin of head lacking a protruding tubercle; no constriction of head 



posterior to eye prominence . . . Sargus Fabricius (sensu stricto, in part) 



Lateral margin of head with a protruding tubercle; head constricted posterior 



to tubercle 4 



4. Eye prominence anterior to protruding lateral tubercle . Merosargus Loew 

 Eye prominence on protruding lateral tubercle 5 



5. Width of head at tubercle not more than 0.5 mm . . . Microchrysa Loew 

 Width of head at tubercle 0.8-1.0 mm. 



Sargus Fabricius (sensu stricto, in part) 



Genus Sargus Fabricius, 1798 



Larvae of this genus are almost impossible to identify to species 

 unless they are fully mature specimens. Earlier instars lack the char- 

 acteristic patterns of the species and the head capsule apparently 

 varies from instar to instar. 



Generic characters. — As given in key to genera. 



Subgenus Pedicellina James, 1952 

 Sargus (Pedicellina) lucens Loew, 1866 



Figures 49, 56, 61 



Description. — Mature larva: length 9.2-11 mm, mean 10.1 mm; 

 width 2.5-3.3 mm, mean 2.85 mm. Other characters as given in key 

 to genera. 



