42 ILLINOIS BIOLOGICAL MONOGRAPHS |360 



setae, uniformly distributed on all aspects; tubercles arranged as follows: the second 

 and third annulets with four tubercles dorsad of the spiracular line, the second 

 tubercle dorsad of the ventral one sometimes rudimentary and often represented by 

 a single tiny seta, the fourth annulet with two tubercles, one on the spiracular line 

 and the other dorsad of it, the sublateral area divided into three lobes and each 

 with one tubercle; the dorsal pair of tubercles of the first annulet with four to five 



setae; on Ulmus; G Macroxyela ferruginea Say. 



8(1) Larvapods very small; thoracic legs rudimentary; body not tuberculate; head 

 creamy whi te ; abdominal segments typically with three annulets ; on staminate flowers 

 of pine (Dyar in 1898 described no larvapods) Xyela minor Dyar. 



Family Blasticotomidae 



The Blasticotomidae contains a single genus and species, Blasticotoma 

 filiceti Klug, which is confined to central and eastern Europe. It is an 

 archaic type. The systematic position of this unique species has been 

 considered differently by practically every writer who has studied it. 

 MacGillivray (1906) has shown, however, that it is in certain of its charac- 

 ters closely allied to the Xyelidae and Pamphiliidae, while in others it 

 approximates the Tenthredinidae, and that, it is intermediate in position 

 between these two groups. 



Because of its taxonomic position, it is highly desirable to know the 

 characters of the larvae of this species, but unfortunately the literature is 

 void of information in regard to the immature stages, and this interesting 

 quest must await future discoveries. 



Family Tenthredinidae 



Larvae (Figs. 7-25) very small to very large, length 10-40 mm.; cater- 

 pillar-like, leaf -feeders, leaf-miners, or fruit-borers; body cylindrical, 

 thorax usually largest in diameter, body tapering caudad, sometimes 

 flattened on the ventral aspect, leaf-miners depressed; greenish or variously 

 colored with or without distinct markings; smooth, glabrous, setiferous, 

 tuberculate, or spinous; segmentation usually and annulation sometimes 

 distinct; third abdominal segment with 6, 7, 5, 4, 3, or 2 annulets, men- 

 tioned in the order of frequency; some of annulets usually setiferous and 

 often with glandubae; thoracic legs always present, usually well developed, 

 typically with five segments, sometimes with three, four, or six segments, 

 but always with distinct tarsal claws; legs rarely rudimentary, fleshy, 

 indistinctly segmented, and without tarsal claws; larvapods present 

 usually on abdominal segments 2-7 and 10 or 2-8 and 10, occasionally the 

 seventh and tenth pairs wanting, rarely with all larvapods obsolete; head 

 typically semiglobose, setiferous, with or without distinct markings or uni- 

 formly brownish, blackish, or greenish; antennae always present, never with 

 m,ore than five segments; ocellarae always present, one on each side; 



