234 Benj. D. Walsh on the Insects inhabiting the Galls 



and the Lobster, the gills are attached to the legs on the outside of the 

 body, because, I suppose, he bad read that this was the case with cer- 

 tain inferior Crustacea. And, on the same page, he asserts that 

 Ephemeridse are among the hugest of insects and lay but few eggs ! ! 

 And again, on the very same page, he asserts that small size is corre- 

 lated with superiority of grade, apparently because a Bee is smaller 

 than a Butterfly, Prof. Dana having asserted the very reverse, viz : that 

 large size is correlated with superiority of grade, apparently because a 

 Lobster is bigger than a Shrimp, and each author seeing only the ex- 

 amples that make in favor of his own hypothesis, and blindly shutting 

 his eyes to those which make against it ; the real truth being that size 

 has nothing whatever to do with the matter. Such hasty and sweep- 

 ing generalizations remind us of the philosopher quoted in one of Ma- 

 caulay's Reviews, (p. 282, Amer. Ed.,) who inferred from a few ex- 

 amples carelessly collated, that all men with two given or Christian 

 names were necessarily Jacobins and Disorganizes, and all men with 

 a single given name were inevitably, in spite of themselves, Tories and 

 Conservatives. In both cases, we have but to take a large number of 

 examples, in order to show the utter fallaciousness of the so-called 

 laws. 



It is singular that, while Latreille described the Teuthredinidous ab- 

 domen as 9-jointed, and Westwood as 8-jointed, neither author seems 

 to have perceived that throughout the family, with one remarkable ex- 

 ception, the % venter is not 8-joiuted, but 7-joiuted. Yet such is the 

 fact, and we have but to open our eyes in order to perceive it. In % 

 Tenthredo, JVematus, Trichiosoma, &c, there are typically 8 dorsal 

 joints to the abdomen, 1 — 7 each bearing a spiracle on its lateral sur- 

 face, and 8 being small, and usually so much retracted as to be in- 

 visible, more especially in the dried specimen, so that the dorsum is 

 often seemingly 7-jointed. As is almost universally the case in In- 

 sects — though Cynipldse form a notable exception — the ventral joints 

 in these groups lie opposite to the corresponding dorsal joints, and we 

 find ventral joints 1--G lying exactly opposite to dorsal joints 1 — 6, 

 while opposite the two dorsal joints 7 and 8, or the one joint 7, if 8 as 

 usual be retracted, there lies only the one large terminal ventral joint 

 7.* On the contrary, in all % lhjlotomidcs. although there are the 

 same number of dorsal joints as in the other Tenthredinidous groups, 



« This arrangement maybe seen most plainly in such species as have the 

 tip of the abdomen differently colored from the rest of it, both above and be- 

 low, e. g. Tenthredo (Allantus) vcrticalis, Say. 



