294 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



1894 there was an excessive drouth, so that but few of the 

 second brood matured. Thus in 1895 there were very few of 

 the insects to be seen. 



Among the birds, the common crow, the red-breasted gros- 

 beak, and turkeys often feed upon this pest to a considerable 

 extent. 



Probably the most destructive insect-parasite of the larvae is a 

 Tachinid-fly known to science as Lydella doryphorce Ril., which 

 rather closely resembles the common house-fly, both in size and 

 color. A single egg is laid on a potato-bug and from it hatches a 

 small, footless maggot which burrows inside the bug. When the 

 larva enters the earth, the effect of the maggot's work becomes 

 apparent, and instead of transforming to a pupa and beetle, it 

 shrivels up and dies; but the maggot itself contracts into a hard, 

 brown pupa, from which the fly eventually emerges. Thus in 

 1868, when first noted by Dr. C. V. Riley, he asserted that in 

 Missouri fully 10 per cent of the second brood and one-half of the 

 third were destroyed by this parasite. 



Many of our common lady-bird beetles and their larvaB check 

 the pest by feeding upon the eggs. Several predaceous bugs, par- 

 ticularly the spined soldier-bug (Podisus spinosus Dall.) (Fig. 213) 



are of value in destroying the 

 larvsB, into which they thrust 

 their short, powerful beaks, and 

 then suck out the juices of the 

 body, leaving an empty skin. 

 One or two of these closely re- 

 semble the common squash-bug 

 (Anasa tristis De G.), but are 

 really very dissimilar, and whereas 

 the beaks of the predaceous 

 forms are short and thick, as in 

 Fig. 213, a, those, of plant-feed- 

 ers, like the squash-bug, are long and slender, as in Fig. 213, b. 



Several species of ground-beetles are often found preying upon 

 the larvae and beetles, but, unlike the bugs, attack them by means 



FIG. 214. Tachinid parasite of Col- 

 orado potato-beetle (Lydella 

 doryphorce Ril.). (After Riley.) 



