402 ENTOMOLOGICAL SOCIETY 



EXPLANATION OF PLATE VI. 

 CLASTOPTERA XANTHOPHALA, var, glaucus. 



a. Chrysanthemum branch showing the spittle. 



b. Terminal part of abdomen of Clastoptera with the anal segment 

 open and in action. 



c. The same in repose and closed. 



d. Young larva. 



e. Grown larva. 



/. Pupa with wing pads. 



g. Winged adult. 



h. Front part of head of adult. 



Mr. Cook read the following paper : 



DUOPORUS, A NEW DIPLOPOD FROM MEXICO. 

 By O. F. COOK. 



As part of a small but interesting series of Mexican Diplopoda 

 collected by Mr. O. W. Barrett, this peculiar member of the 

 order Merocheta is worthy of special mention. It agrees with 

 Stenodesmus Saussure and Biporodesmus Attems, and differs 

 from all other known Diplopoda in the possession of but a single 

 pair of repugnatorial pores, located on the fifth segment. But 

 notwithstanding the resemblance in this particular, it is evident 

 that the new form has little, if any, affinity with either of the 

 above genera. Stenodesmus, also a native of Mexico, is a large 

 animal (65 millimeters) with a granular-tuberculate dorsal sur 

 face and a spine on the second joint of the legs, which last feature 

 has been supposed to ally it with Fontaria. The South Amer 

 ican genus Biporodesmus is also an animal of considerable size 

 (45 millimeters), with a flat or concave, granular dorsum, a ver 

 tex sulcus, and complex, three-pronged copulatory legs, to say 

 nothing of minor discrepancies. The new genus, to be called 

 Duoporus, has a small, rather slender body, much narrower behind 

 than in front, and gradually tapering from near the head. The 

 dorsal surface is strongly convex, smooth and shining, and the 

 posterior corners of the carinaB are long and spiniform. The 

 copulatory legs are remarkably simple, the second joint consist 

 ing of a simple falcate process ; they thus bear a much greater 

 general resemblance to those of Sphagriodesmus than those of 

 Biporodesmus. 



The existence of three such distinct types with the same pore- 

 formula is, however, but one of many evidences that pore char 

 acters, though of great systematic utility in the Diplopoda, do not 



