22 
In their life history blister beetles differ greatly from other Cole- 
optera in that they undergo a more complicated series of metamor- 
phoses which will be explained and illustrated in the account of the 
striped blister beetle which follows. 
Blister beetles are not an unmixed evil, since they do some good in 
their larval stage to compensate in a measure for the harm the beetles 
occasion to our crops, for the habit of the larvae of destroying grass- 
hopper eggs renders them of material aid in keeping these pernicious 
insects in check. This is especially true in the W.estern States, where 
both blister beetles and grasshoppers abound. But the benefits derived 
are really more than counterbalanced by the losses occasioned in fields 
and gardens; hence, insecticides and other measures should be 
employed to destroy the beetles when they occur in harmful numbers. 
As blister beetles are to be found in practically all fields of sugar 
beet, and are among the most prominent enemies of this plant, it is 
purposed to consider several of the most abundant species. 
THE STRIPED BI.ISTER BEETLE. 
[Epicauta vittata Fab. } 
Before the advent of the Colorado potato beetle in the East this was 
our most destructive potato insect, and probably because it is also 
he 
Fig. 13. — Epieauta vittata: a, female beetle; b, eggs; c, triungulin larva; d, second or caraboid stage; 
€, same as /, doubled up as in pod: /, scaraba&oid stage: cj, coarctate larva — all except e enlarged 
(after Riley, except a; original, Division of Entomology). 
striped is often called the "' old-fashioned potato bug."" It is abundant 
and well known east of the Rocky Mountains, of common occurrence 
on sugar and table beets, and as its life history is typical of injurious 
forms of this group it may properly receive first attention. The beetle 
can be easily identified by means of the illustration (fig. 13, ^/). It is 
about half an inch long, and there are two black stripes on each wing- 
cover, alternating with yellow. . 
The eggs are laid in small masses (h) on plants or upon the ground. 
From each hatches a small long-legged larva, called a "triungulin "' (c), 
which runs actively about in search of a grasshopper egg pod. which 
