16 



could not be the same pressure in them or in their neighbour- 

 hood inside the tin, as in cylinders A and D. The beetles 

 working their wav upwards to the top surface in the tin are 

 certain to feel the difference as soon as they come within 

 the area and make for the direction where pressure is less. 

 That it is so is proved by the fact that no beetles appeared 

 in those cylinders where the seeds were pressed back by 

 paper discs. The negative geotropism exhibited by the 

 insects appears thus to be directly caused by the weight of 

 the seeds above them which they feel when they emerge. 

 As they move upwards this weight becomes less and less 

 until it disappears completely when they reach the top 

 surface. 



The pest appears to be carried over from year to year 

 hy the adults. Adults have been taken from situations near 

 which pulses were stored. They have also been taken in the 

 field in seasons of the year when the crops which they attack 

 are not yet ripe. At the time of harvest, a number of pods 

 are dry and open. The beetles get at the exposed seeds in 

 these pods and lay eggs on them. Infestation may also take 

 place during the interval between harvest and storage or in 

 the store itself. In one instance where multiplication had 

 leased for over a year in a quantity of infested seeds kept 

 in a bottle, a fresh attack ensued in spite of the fact that the 

 jar was never opened during the interval. 



Three species of parasites have been reared out, of which 

 two are black-bodied species, one large and the other small. 

 These do not multiply in large numbers proportionate to the 

 number of beetles until the infestation has advanced far. 

 They are, therefore, of little use as checks. As many as six 

 have been reared out from one larva but the number varies 

 and probably depends on the size of the larva at the time of 

 oviposition. Boring has been observed to take place through 

 the egg shells and through the other parts of the seed far 

 removed from them. The following is an account of obser- 

 vations made by Dr. Coleman and kindly furnished for this 

 bulletin :- — 



"Female parasite explored surface of seed with feelers 

 bent down. Then she raised herself and brought tip of 

 abdomen down between the hind legs in almost vertical 

 position. The tip of the abdomen was then moved away 

 posteriorly leaving the tips of ovipositors in a vertical posi- 

 tion. Boring did not immediately take place, but tips of 

 ovipositors were moved about on the surface of egg as 

 if seeking the most favourable point for penetration. 



