44 NATURAL SCIENCE [January 



and it is amongst those that the true relations of Dipcltis will pro- 

 bably have to be sought. The abdomen of Dipeltis is narrower in 

 proportion to the thorax than is the ease with existing cockroaches, 

 but a similar condition may be seen in the figure of the fossil larva 

 referred to above ; and if this figure be compared with the figures 

 of Dipcltis one cannot help being struck by the agreement in general 

 shape, and in the number and relative size of the parts. 



In the facts, apart from the speculations, which are disclosed in 

 Mr Schuchert's account of Dipcltis, I find nothing that is inconsistent 

 with the view I have ventured to put forward in this paper ; while 

 it is interesting to note that " these animal remains are found in 

 [Lower Coal Measure] nodules associated with Prcstivichia, Etiryjy- 

 terus, malacostracous, schizopod and decapod crustaceans, arachnids, 

 insects, Aviculopccten and Solcnomya, and numerous ferns." 



Dr Packard, who established the genus Dipcltis, is a distinguished 

 entomologist, and may very well be trusted to recognise a fossil 

 insect when he sees one. But so far as I am aware he has not yet 

 expressed an opinion upon the more perfect remains that have come 

 to light since he first described the genus from a mere fragment of a 

 specimen. I shall be anxious to know what that opinion is, and 

 shall be surprised should it not support my own view of the present 

 question. C. J. Gahan. 



[I may as well at once confess that, until my attention was 

 called to them by my entomological friends, I was quite ignorant of 

 the existence of insects, either adult or larval, showing the habit of 

 Apus so nearly as does Dijjeltis. I venture to submit that very few 

 zoologists, who are not specialists in entomology and acquainted 

 with these particular forms, would recognise anything specially 

 Hexapodan in Dipcltis, which does not even show the ordinary insect 

 segmentation with its antennae-bearing head. I do not, therefore, 

 think that much blame attaches either to Mr Schuchert or myself 

 that we failed to detect the insectiform characters of Dipcltis, hidden 

 away as they are under the guise of Apns. 



Leaving, however, this unimportant personal question, I think 

 it may be easily gathered from my remarks on Dipcltis, in the paper 

 referred to by Mr Gahan, that the Apodidae would not lose much by 

 giving it up. Its claims to belong to that ancient family required 

 a strong pair of pincers to bring it into line. This is, I think, the 

 chief argument in favour of Mr Gahan's claim that Dipeltis belongs 

 to the entomologists : it fits easily into their system, thanks to the 

 existence of certain larval forms, but only with great difficulty into 

 the Apodidan. But for this difficulty, which is, by the way, only 

 revealed by careful analysis, we should have to wait for further evi- 

 dence before coming to any definite decision as to its affinities. — 

 H. M. B.] 



