98 Weevils of the Genus Si ton a 



Legs. Femora black but reddish at the base and extreme apex and 

 bearing pale scales and long flat setae. Tibiae and tarsi red clothed with 

 similar setae. 



Antenae. Dark red with pale setae. 



External Sexual Differences. 



The sexes can readily be distinguished by examination of the posterior 

 abdominal segments which are similar in structure to those of S. lineata. 



On Distinguishing Sitona hispidula from other British Species of Sitona. 



Owing to the difficulty usually experienced in identifying the weevils 

 of this genus, and in order to supplement the key already given, the 

 species which might most easily be confused with S. hispidula are here 

 enumerated and some additional characters for their distinction are 

 given. 



S. tibialis Herbst and S. lineella (Jyll. Bristles more depressed and 

 much shorter than in S. hispidula, not being as long as breadth of an 

 elytral interval. 



S. crinita Herbst and Waterhousei Walt. Eyes prominent, projecting 

 from the sides of the head. 



S. regensteinensis Herbst. Anterior coxal cavities reaching presternal 

 line (Fig. 4). 



S. humeralis Steph. No upstanding setae. Forehead excavated 

 between the eyes. 



The Reprodiicfive Organs of Sitona hispidula. 

 The reproductive organs of S. hispidula are similar in structure to 

 those of S. lineata, but in the male differences occur in the shape of the 

 genitalia. In the newly emerged female of S. hispidida the ovarian tubules 

 are scarcely developed and the terminal chambers are very small, just 

 as in the immature female of S. lineata, but unlike this species, the 

 reproductive organs of both sexes attain full growth 6 to 8 weeks after 

 emergence. 



Alary Dimorphis?n^. 



In the course of dissection of Sitona hispidula F. it was observed that 

 two forms of the species existed, one with fully developed wings (Plate III, 

 fig. 1) and the other with very small vestigal wings of a peculiar shape 

 (Figs. 2 and 3) and incapable of flight. The brachypterous wings vary in 



^ A similar case of alary dimorphism is described by Dr David Sharp in the Carabid 

 Pterostichus (Omaseus) minor Gyll m The Entomologist, vol. 46, 82-87, 1913. 



