Spines in Dactylispa xanthopus, Gestro. 



71 



collected by Fruhstorfer from Sikkim as D. xanthopus, but 

 points out that each side of the prothorax has got two spines, 

 but lie considers this circumstance an anomaly. He is quite 

 right in thinking so. The object of this note is to show the 

 variation in the number and formation of the prothoracic 

 spines of 1). xanthopus. 



From the numerous examples before me it can be safely 

 concluded that the normal number of the prothoracic spines 

 is four on each side, and a pair of triple spines on the front 

 margin — i. e., three spines standing on a common stock. 



Variation in the Spines on the Front Margin. 



^ Normally there is a pair of triple spines. The horizontal 

 distance between them is as usual in most species of the 

 genus. The spines stand erect j the first is always an 

 appendix to the second arising from its front side ; it may 

 arise cither near the base (fig. 2) or a little above (fig. 3), its 



Dactylispa xanthopus. 



Figs. 1, 2, 3, 4 are marginal spines at the front ; 5, G, 7 are the lateral 

 groups of spines. The spines on the right of the figures point 

 towards the head. 



length may be quite small or it may attain the length of a 

 normally developed spine (fig. 4), but it is always smaller 

 than the second spine. The latter, together with the first, is 

 slightly inclined forward. The third stands almost vertical 

 and is the longest. The first spine may be entirely absent 

 in some cases (fig. 1). Occasionally in the same individual 



