ee ee 
THE ROUGH-HEADED CORN STALK-BEETLE 99 
and is characterized by its large, nearly rectangular clypeus which 
is separated from the epicranium by a distinct clypeal suture. The 
surface of the head is smooth except for a number of rather sparse 
punctures and is entirely devoid of either rugule or a transverse 
ridge. 
CYCLOCEPHALA spp. | 
The only stages in the life history of Cyclocephala likely to be 
confused with Huetheola rugiceps are the larva and the pupa. The 
larvee of Cyclocephala are somewhat smaller than those of F. rugi- 
ceps and of more yellowish hue. They also differ in the smooth 
and shiny surface and yellowish amber color of the head shield and 
in the entire absence of any trace of a median double row of modi- 
fied bristles on the last ventral segment. The distinctive character 
of the pupa was not fully studied in this investigation, but the 
possibility of confusing it with the same stage of Euetheola is 
largely eliminated by the fact that the two occur at entirely dif- 
ferent periods of the year. Thus, at Tappahannock, pupe of 
Cyclocephala were obtained from the last of May to the early part 
of July, whereas those of #. rugiceps were never taken before 
August. 
PHYLLOPHAGA spp. 
So far as adults of Phyllophaga are concerned there need be no 
difficulty in distinguishing them from H'uetheola rugiceps, while the 
larve may be recognized by the reduced size and triangular outline 
of the supraanal plate, the angular form of the anal slit, the smooth 
and shiny surface and yellowish color of the head shield, and the 
presence of a conspicuous, sharply defined, double row of modified 
bristles on the last ventral segment (PI. II, @). ; 
NATURAL ENEMIES 
The data on the predacious enemies of Hwuetheola rugiceps are 
very incomplete, and little of importance has been added in the 
course of this investigation. The underground habits of the species 
render it difficult to obtain direct evidence of predatory enemies, 
and only a very small proportion of the individuals collected were 
parasitized. 
At Tappahannock the fields infested with 2. rugiceps were ob- 
served to be frequented by flocks of crows, grackles, and bobolinks, 
which were probably feeding upon the beetles, though direct proof 
of this was not obtainable. The Bureau of Biological Survey, 
however, has found specimens of #’. rwgiceps in the stomachs. of the 
crow, meadowlark. and bluebird, and of species of the closely related 
genus Ligyrus in the stomachs of numerous birds. 
Among the possible insect foes of #. rugiceps may be mentioned 
several species of Carabidae (ground-beetles), Asilidae (robber- 
flies), and ants. Carabia beetles were normally common in under- 
ground situations and were of frequent occurrence in the places 
where /. rugiceps has been found, but the writers have no direct 
evidence that they attack or kill the latter, though it seems likely that 
the smaller larvee, at least, may at times be the victims of these pre- 
dacious beetles. As for the Asilidae, Titus (73) mentions the larva 
