446 Mr. Gilbert J. Arrow's Classification of 



applied the name dilatahts to the allied P. politiis, Burm., 

 as has long been known. As the species to which the 

 name cancrus has hitlierto been assigned is a well-marked 

 one for which no other name is available it will be well to 

 call it Tiberius Jcuivcrti. 



Certain of the most remarkable forms of Passalidse have 

 not yet found their proper places in the system. The 

 genus Cylindrocaulus of Fainnaire, a curious Chinese 

 insect, and the Mexican Spurius hicornis, Truqui, were 

 together made into a sub-family by Kuwert, a strange 

 proceeding due only to the absence in both of the median 

 cephalic horn common to most sections of the family. 

 Cylindrocaulus Ijuccrus, Fairm., is an apterous insect of 

 very peculiar form, but still more peculiar is Aulacocyclus 

 patalis, Lewis, an allied Japanese species for which a new 

 genus Aurikidus has been made by Zang. It was de- 

 scribed and figured in the Trans. Ent. Soc, Lend., 1883, 

 p. 841, PI. xiv, figs, 6 and 7, but was overlooked by 

 Kuwert. In both species the disc of the thorax is drawn 

 out in front into a bifid protuberance, a feature very 

 strange for this family, although slightly suggested by the 

 form of the thorax in CcrcUocupcs, and it is in the vicinity 

 of that genus that other essential characters of these forms 

 place them, although probably the most aberrant species 

 in the family. In C. hucerus the front coxas are separated 

 by a strongly elevated lamina, which is an infringement of 

 a main feature of the Aulacocyclinai, but in A. patalis the 

 coxEe are more elevated than the intervening lamina, 

 which is so much reduced that they are practically con- 

 tiguous in the middle. The very short connate elytra 

 (indicating inability to fly) are also quite exceptional, 

 the only flightless Passalidas hitherto recorded being of 

 American genera. A. j^atcdis, Lewis, has the elytra even 

 shorter relatively and more bulbous than C. huccrus, 

 Fairm., which I have been kindly enabled to examine by 

 M. Oberthiir, who possesses also an undescribed insect 

 from Wa-shan which, although head and thorax are formed 

 like those of Cylindrocmdus, is winged and has the hinder 

 part of the normal shape. The head in these beetles is 

 quite smooth and concave, and its lateral walls are pro- 

 duced above the eyes into a pair of horns, which in C. 

 hucerus are slender and pointed and in A. paialis flattened, 

 widening from base to extremity, where they are truncated 

 by an incurved line. In the latter insect there is also a 



