74 



AN ECONOMIC ENTOMOLOGY. 



the farmer. There are several sub-families, which together are 

 termed "lace-winged flies," from their delicate, finely-reticulated 

 or netted wings, which lie flat and are not folded. The insects 

 are slight, and in the species allied to Hemerobius the colors are 

 brownish or smoky. They are less common than the forms 

 allied to CJuysopa^ which are green, with long antennae and 

 prominent, bright, yellowish-brown eyes, which have given them 

 the name * ' golden-eyed flies' ' in some localities. They are 

 commonly found in fields or along the edges of woods, and emit, 

 when handled, a peculiarly sickening odor which is quite unmis- 

 takable when once known. In the adult stage the insects feed 

 little or not at all ; but the larvae, known as "aphis-lions," feed 

 almost constantly, their prey being small, soft-bodied insects of 

 all kinds, aphids or plant-lice ranking as special favorites. 



Fig. 40. 



A lace-winged fly, Chrysopa oculata. — a, the eggs ; b, the larva ; d, same, feeding on a 

 pear-psylla ; e, cocoon, from which /, the adult, has escaped ; g, head of adult in front, 

 enlarged. 



The entire life history of the insects is interesting. The female 

 in ovipositing touches the end of the abdomen to the surface, — 

 usually a leaf, — upon which the eggs are to be laid, and then 

 elevates her body about a quarter of an inch, emitting at the 

 same time a viscid thread which hardens on exposure to the air. 

 At the tip of this the egg is fastened, and we get thus a little 



