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eleven-jointed antennae, is, despite the difference in the form of these an- 

 tennae most closely allied to them. Now as the Geotrypini are laparosticti 

 Lamellicornes I consider myself justified in placing this genus which also 

 has but eleven antenna! joints in this division. That this placing was 

 due only to reasoning by analogy, extraordinary as it may seem, is forced 

 upon one by the fact that he nowhere speaks of having examined the ab- 

 domen for the position of the stigmata, and positively mentions that the 

 specimen first described by him had had the abdomen destroyed. 



But what, actually, is the structure of this abdomen ? Undoubtedly, 

 in view of the many characters contradicting the relationship with the 

 Geotrypini, an answer to this question was of primary importance, because. 

 pro- or con. decisive. I, therefore, with the growing conviction that Pleo- 

 coma had nothing in common with the Geotrypini, but despite the eleven- 

 jointed antennae, could belong only to the Melolonthini, did not hesitate 

 a moment about obtaining certainty by an examination of the carefully 

 removed abdomen of one of my specimens. This examination proved 

 positively, what I fully expected, that the large spiracles of the second ami 

 third, and the smaller ones belonging to the fourth and fifth abdominal 

 segments, had, in Pleocoma, precisely the same situation as in Melolontha, 

 i. e. on the superior portion of the ventral segments, and not on the 

 membrane connecting the corneous dorsal and ventral plates as in Geo- 

 trypes and Copy is. 



From this it appears at once that Pleocoma does not belong to the 

 Scarabceidce laparosticti "d\ all, and that the relationship assumed by Leconte 

 to exist between this genus and the Geotrypini and Coprini&s at first stated, 

 or the Geotrypini and Trogini, as finally stated, was entirely without base. 

 Certainly he would have been much nearer right in the conviction at first 

 forced upon him, of its relation to the Dynastmi as, agreeing with them, 

 this insect is at least a phurostict. But that, even disregarding the entirely 

 different situation oi the spiracles, Pleocoma shows no real relationship to 

 the Geotrypini but only a certain habitual agreement with some of them, 

 and an agreement in unimportant details with others is fully demonstrated 

 by an examination of all really important characters. 



As to the habitus of Pleocoma, it is not to be denied that it reminds 

 one of the females Ceratophyus, Fish:; but of all the Geotrypid forms it 

 reminds one of that only. As Leconte himself says a closer comparison 

 is at once opposed by the entirely different sculpture of the elytra, and 

 in this respect the resemblance to Syrichthus would be vastly more ob- 

 vious. Further, as regards the agreement of the prosternum with that 

 of Athyreus prominently mentioned by Leconte, I am utterly unable to 

 discover any such ; in Athyreus it forms an inflated trigonate or heart 

 shaped plate, and at this point in Pleocoma there is only a small. 



