284 Transformations and Habits of Blister-Beetles. [ May, 
no difficulty, under my directions, in finding them last May j; 
Manhattan; while they were sent to me among other locust-egg 
parasites by Mr. Seth H. Kenney of Morristown, Minn., and from 
St. Peters in the same State by Prof. Cyrus Thomas. 
From such larvæ preying on the eggs of C. spretus I have reared 
the unicolorous form of Epicauta cinerea (Forster), or the margined 
Blister-beetle!; the Lpicauta pensylvanica (DeGeer)? or the 
Black Blister-beetle; the Macrobasis unicolor (Kirby) or the ash- 
gray blister-beetle; and the form of it described as murina by 
LeConte, or the black-rat blister-beetle. 
Since then I have found it very easy to trace the larval habits 
and development of the two more common potato-feeding species 
around St. Louis, viz: the striped blister-beetle (Epicauta vittata, 
Fabr.) and the Margined Blister-beetle (marginata Fabr.) just 
alluded to. 
Careful examination of locust eggs in the vicinity of potato 
fields frequented by these beetles show a varying proportion of 
the egg-pods affected, and in some locations nearly every pod © 
the differential locust (Caloptenus differentialis) will contain 
the Epicauta larva. The eggs of this locust are laid in large 
masses of 70 to 
about 100. The pod 
is but slightly bent, 
rather compact out- 
i = side, while the eggs 
Fic. 5.—Caloptenus differentialis. are irregularly ar- 
1The black, gray-margined form, very appropriately described by Fabricius as 
marginata, is referred to cinerea Forster by modern systematists, and “specifically 
united with it by Dr. Horn. Yet the fact remains that the two are not ordinarily, } 
ever, found commingled. The margined form is very common in potato fields in 
issouri. It shows little variation and is found almost invariably in conjunction 
with z¢fata, but not with the unicolorous form in question, which is most com mmon 
farther west and occurs abundantly without the margined form—all "on is against 
p specific union of the two. 
E. atrata Fabr. 
3 — M. cinerea Fabr., Fabricii Lec., murina Lec., debilis Lec. I accept Dr. Horn’s 
conclusion that the last two are but poorly developed forms of this species. Yet the 
m a form is not due to te or injury, but issues from the pupa without 4 
trace of gray scales on the elyt 
= E. lemniscata Fabr. Dr. Han retains /emniscata as a distinct species in his 
_ Revision already referred to. The outer stripe in the bi-vittate specimens divides up 
in others so as to give the tri-vittate character on which /emniscata is founded. Both 
extremes and every possible variation between them occur constantly together in the 
same potato field in Missouri, and there are no other differences of specific valu 
af 
