89 



chinch bugs sufficiently free from it to make them suitable subjects for experi- 

 mental attcmi)ts at its transfer. It will bo readily iimlerstood by any one that it is 

 useless to test the utility of artiticial cultures of the disease germs by applying them 

 to insects which are alrea<ly atfected by the disease in question. The first step of 

 any really scientific investigation of the econ<imics of this matter is to determine 

 positively the absence of the disease in the lots of insects to be used in the experi- 

 ments. Every lot of chinch bugs thus far obtained by me from central, south cen- 

 tral, and northern Illinois during the months of July and August of this year gave 

 evidence, under critical study, of the presence of this microbe in the c(Bca of 

 a larger or suuiller percentage of pupai and imagos. My previous observations — less 

 carefully made, however, than my recent ones — have been to the general effect that 

 hibernating chinch bugs and young preceding the so-called pupa state are little 

 liable to the spontaneous occurrence of the intestinal trouble, and I consequently do 

 not despair of finding, before the present season is over, oi)portunity for experiments 

 which will determine beyond (question the economic value of this chinch bug 

 cholera. 



In comparing this with similar human diseases we must take account of the 

 poverty of the circulatory fluid of the chinch bug and the simplicity of its circula- 

 tory apparatus, which forbid the marked development of any of their phenomena of 

 fever or inflammation. Indeed, it seems to me that insect diseases generally are 

 characterized by the absence of a vigorous physiological reaction which their rela- 

 tively low structure, nervous and circulatory, makes impossible. Th(i features of 

 this disease, for example, I think may be wholly accounted for, consistently with the 

 physiology of the insect, as results of the simple destruction of the epithelium of the 

 coeca and the consequent suppression of the functions of those organs, combined 

 with the toxic efiects of the pioducts of bacterial action. 



Is it not quite possible that the student of pathology may find in the study of the 

 diseases of those lower forms of life, experiments prepared for him by Nature which it 

 would be quite impossible for him to imitate on animals of more complicated sensi- 

 tive and sympathetic organization ; and that he may thus sometimes simplify a 

 problem whose complexity must otherwise prevent its solution? 



Injurious insects of New South Wales — Since we last referred to the 

 entomological matter in the Af/ricultural Gazette of ]^eiv South Wales, 

 we have received parts 4, 5, aud G of volume ii. Mr. Olliff has, in part 

 4, an interesting article on the Fig Leaf Beetle {Galerucella semipuUata), 

 a species which feeds in all stages on the young shoots and foliage of 

 wild and cultivated tigs. Figures of all stages are given, as well as a 

 detailed account of the life history. Spraying with Paris green is rec- 

 ommended as a remedy. In i)art 5 the same author treats of a Tachinid 

 parasite of the Plague Locust, tigurifig it in all stages, and giving a 

 technical description by Mr. F. A. Skuse under the name Masicera 

 pachytili. This parasite has appeared in great numbers, and in one 

 locality from <)0 to 70 per cent of the grasshoi)i)ers were affected by it. 

 He also makes some mention in the same number of a species of Chermes 

 on Pine, the Oyster-shell Bark-louse of the Apple, and the Orange Rust- 

 mite. In part G, Mr. Olliff' publishes an account of the Pine Case-moth, 

 Oiketicus liuehneri, with a full-page i)late illustrating its transformations. 

 It is closely related to the Bag Worm of the United States, and has 



