252 Mr. E . Saunders' further notes on the 



and is rarely visible ; as a rule it fits into and is of the 

 same shape as the 7th, but there is an important modi- 

 fication of it in the Heterogyna, MutilUdce and Pompilidcs, 

 and the genus Astata, where it bears at its apex two 

 little pilose processes of a somewhat palpiform nature 

 (see PL XIII., figs, la, 2a, 3a, &c.) : these are generally 

 visible beyond the apex of the 7th segment, and will be 

 found more fully described under the head Heterogyna, 

 &c., further on, where the distinctive features exhibited 

 by the terminal segments in each family and genus that 

 I have been able to examine are noticed in natural order. 

 It seems to me that these features, although unfortu- 

 nately only existing in the ^ sex, afford far better 

 characters for classification than the neuration of the 

 wings, which have formed the basis of the arrangement 

 of the Fossores, &c., which we now use. We know how 

 subject neuration is to vary, and how often specimens 

 are found with one or more nervures of the wing im- 

 perfect or missing ; also how in a series of specimens of 

 one species a certain nervure will vary in its exact rela- 

 tive position to another ; also how in Tropoxylon there 

 are several cells merely indicated, as it were, by the 

 very faintest nervures, besides those enclosed by ner- 

 vures of the ordinary size, so that classing it by the 

 ordinary nervures it takes its place amongst the genera 

 having only one submarginal cell ; whereas, if the entire 

 system of neuration be admitted, it would come amongst 

 those with two. 



There is, I think, also very grave doubts whether the 

 insect we know as Pompilus pectinipes is more than a 

 variety of the 2 of Evagcthes hicolor, with three sub- 

 marginal cells instead of two, which is the characteristic 

 of the latter genus. Certain it is that the two forms 

 often frequent the same locality, and that the 3" of 

 pectinip)es, the ? of which is far from rare, is unknown 

 to us (the (? which F. Smith refers to it is that of chaly- 

 heatus) ; and specimens have occurred with three sub- 

 marginal cells on one side and two on the other. All 

 these variations in neuration make it to my mind a 

 very dubious character for classificational purposes, 

 and, if the characters derivable from the terminal seg- 

 ments could be used instead, I think they would probably 

 afford a more natural arrangement, and be far more 

 constant. I say this after carefully observing that a 

 certain type of segments will run through a whole genus, 



