96 MR. R. W. JACK ON THE LARV.E 



The habits o£ the larvae and adults and the life-history are 

 similar to those of G. 8e quale, witii which this species is 

 commonly associated in great numbers. Emyon tristis is, 

 however^ found more al)undantly on the sand veld than 

 G. re quale. 



General Notes. 



The eggs of all species studied are laid loosely in 

 the soil. The newdy hatched larva3 are comparatively 

 soft and are different in form from older specimens, 

 being stouter in proportion to their length. After a few 

 days, however, they become chitinous and more elongate. 

 The larvfie which attack crops are generally called " wire- 

 worms" in Rhodesia owing to their resemblance to Elaterid 

 larv?e. The term "Surface Beetles^' is applied to Gono- 

 cephalum, Emyon, Zophosis, etc., which are chiefly 

 conspicuous for their attacks in the adult stage on seeds, 

 newly planted tobacco, etc. This name was originally 

 applied by Lefroy to Opatrum (Gonocephalu m ) in India. 



The difference in the various life-histories is verv interest- 

 ing, but it is a per])lexing undertaking to attempt to 

 understand the purpose of these variations. The en.ergence 

 of the imago nt the commencement of summer and the 

 ])Ostponement of egg-lajing until the first touch of autunm 

 is in the air, as in the case of Gonocephalum, Enn'on 

 and Zophosis, is surely most unusual amongst insects. It 

 is noteworthy, however, that all three species occur on the 

 dioritic loam, which forms an exceedingly tenacious mud in 

 the wet season, and it miiy be that this environment does not 

 suit the young larvrc as well as dry conditions. Trachy- 

 notus lives over the wet season in the larval staoe, but the 

 larva? have attained considorjible frrowth before the rains 

 start. The other species, which lay eggs at the beginning 

 of the rains, are mainlv denizens of the sand veld. 



