30 JOURNAL OF THE [January, 



Upon dissection of a beetle, either in its larval or perfect 

 form, it will be found that the muscular system is most complex 

 in the head. This is rendered necessary by the work demanded 

 of the head-organs, especially the mandibles. Harpalus calig- 

 inosus, which I have selected as a type, belongs to the Carabidce, 

 or carnivorous beetles, and, like all of its family, renders great 

 service to mankind by feeding upon other insects, which are in- 

 jurious to vegetation. It is one of our most common American 

 species, and may be seen, in company with the more gaudily- 

 colored CalosomcB, busily engaged in hunting for its prey. And 

 although not so attractive to the eye as the others, it is fully as 

 destructive to insect life. Woe betide any insect that comes 

 within the range of its eyes. From the soft-bodied Aphis to 

 the almost metallic-coated Buprestian, all is " fish " that comes 

 to its net, in either larval or perfect form. Its larva is equally 

 as destructive. I have seen a female Harpalus seize a Biipres- 

 tis — the Chrysobothris Harrisii, the body-crust of which is hard 

 enough to turn the edge of the best scalpel made — and rend it 

 to pieces with its mandibles, in a shorter time than I have taken 

 in the description. 



By examining the inner surface and contents of the head, it 

 can readily be seen from what source the immense strength pos- 

 sessed by the mandibles is obtained. Almost the whole con- 

 tents of that portion of the body consist of muscle-fibres, acting 

 directly upon its organs. A look at the hurriedly-prepared dis- 

 section of the head of one of these beetles, which is here on ex- 

 hibition, will show this fact. Everything but the muscle-fibres 

 has been removed, and only the large flat or round fibres re- 

 main. Several of these at their front ends form their connec- 

 tions with the mouth appendages, but still connect with the 

 head by their rear ends. It can be seen that they are arranged 

 in various layers, or, as Newport calls them, systems. Lyonnet 

 counted in the head of the Cossus some 228 distinct muscles. I 

 have not counted those in the head of Harpalus, but should 

 judge that they were fully as many. This number seems almost 

 incredible. Yet, when we consider the various appendages of 

 the head which are dependent upon these muscles for their vari- 

 ous movements, it is not so wonderful. The movements of the 

 antennae, of the mandibles, of the various other parts of the 



