ZOOLOGICAL DEPARTMENT. 



307 



quickly convince the most skeptical of the valuable service 



of these predaceous friends. When full grown the larvaet 



pupate on a straw or some blade or twig. I have in ourj 



collection a cherry twig which contains a score or more 



of these dark, rounded pupae. The pupae (Figs. 6 and 7) 



are exceedingly small compared with the larvae and mature Fig. 7.-Larva, Pupa 



beetles. These lady-bird beetles are hardly second to the and Beetle- _ 



Braconid parasite, in the work of ridding our grain fields of the lice. 



Prof. 0. M. Weed tells me that he believes in Ohio they take a first place in 



this important service. 



T7ie Syrphus- Flies. 



By close watching in the wheat or oat fields we observe a large number of 

 very rapid flying two-winged flies. These are not only very quick, but many 



are lined (Fig. 8) with yellow bands and are very beauti- 

 ful. These flies, for food, only sip the sweets from flow- 

 ers, but they lay their eggs on the plants among the 

 aphides, and the maggots that hatch from these are per- 

 fect tigers. These syrphus-maggots seem to be veritable 

 \gourmands, as the number of plant-lice that one will 

 suck bloodless is surprisingly great. These maggots 

 (Fig. 9) look some like leeches or blood-suckers. The 

 posterior end is large and truncated, while the mouth 



Fig. 8,-Syrphus-Fly. end . g pointed> The color of the young oneg j g oliye 



green, while the older or more mature maggots are gray, brown • 

 or purple. There are light brown transverse bands on the 

 back and one longitudinal one on each side. These maggots 

 creep along in a slug-like manner, ever reaching into every F ^^syrphus 

 crevice for the lice. The energetic zig zag motion of the head plant louse. 

 is very interesting. When it first finds a louse it stabs him with its sharp 

 mouth-parts and quickly sucks him bloodless. As the louse shrinks the 

 maggot swells up. No sooner is one louse victimized before another is 

 seized, and thus these voracious maggots will often destroy a half score of 

 lice in quick succession. My students have often suggested that these mag- 

 gots must have india rubber stomachs. From their great numbers and 

 ravenous appetites we must conclude that these syrphus-maggots are little, 

 if any, behind the Braconid fly and the lady-bird beetles in their good ser- 

 vices in helping to save the grain crops. 



Cry sop a- Flies. 



These beautiful green lace wings, with their brilliant golden eyes (Fig. 10), 



p » are no mean factor in this warfare against 

 [// plant lice. The handsome flies do not feed 

 on the lice but the larvae do, and as they have 

 'insatiable appetites they do excellent execu- 

 tion. These flies lay their minute white eggs 



JX. 



Fig. 10.— Chrysopa-Fly and Eggs. 



