256 



HALF-AN-HOUR AT THE MICROSCOPE. 



general body of science. Surely, some of our members will take 

 this desiderata up. E. T. thinks it is from a gooseberry saw-fly 

 (Nematiis grossidaria). Well, then, get one of these, dissect it, 

 and see. If his supposition be correct, well and good ; if not, 

 still a sound knowledge of these parts in this insect will have been 

 attained, and inquiries must be continued till the insect has been 

 truly ascertained. I must be pardoned for pointing out that to 

 the eye of science none of these things have more than a very 

 trifling value until their habitus be known. 



Gizzard of Curculio, and 



Gizzard of a Beetle (PI. XXI., Figs, i — 8) (see notes by Dr. 

 Case and A. Nicholson (p. 257). — If our friend's reason for not 

 giving the name of his beetle be (as we may, perhaps, be justified 

 in suspecting) that he does not know it, the retort might be per- 

 missible, " Well, doctor, you ought to know ! " The contributor 

 of Curculis Gizzard says (if I read his remarks aright) that it 

 came from a beetle of the same species, and this would fix 

 its origin to a weevil. But amongst so numerous a tribe, and of 

 which the minute internal anatomy has been so little studied sys- 

 tematically, this does not carry us a very great step forward. And 

 as there appears some serious errors with description, it will be 

 necessary to say a few words introductory to a consideration of 

 the subject generally. 



The alimentary canal in insects is 

 composed of i^gu.) oesophagus or gullet, 

 (^.) crop, (^.) gizzard, (.f.) true stomach, 

 {s.i.) small intestine, (/./.) large intestine, 

 and (;'.) rectum. The food taken in at 

 the mouth passes first through the gullet 

 to the crop, which is often very large, 

 and is then passed on for trituration to 

 the mill seated in the gizzard. The 

 teeth with which the latter is furnished 

 vary much according to the nature of 

 the work to be done. In the cockroach 

 they are few, of large size, dense and 

 horny. In the cricket the teeth are 

 numerous, arranged in bands of differing 



Jn^ form. In the weevil, as we see in the 



drawing, the form of lepidopterous scales 



In the earwig, minute crowded spines in patches. 



there appear to be two kinds : at the upper part, 



long, sharply-pointed prisms ; at the lower, short teeth, with three, 



four, or five curved cusps. In the bee they resemble simple hairs. 



Whilst in some cases these projections from the inner walls of 



.XJ. 



is assumed. 

 In the flea 



