497 



position upou tliem bj Bruclnis pndiii)ius wliieli has otherwise 

 been quite ready to oviposit upon very diverse seeds. 



The seeds of Delonlx regia, Acacia grandis, and of Pelto- 

 phorum inerme among others are covered with a very dense and 

 hard covering and it is doubtful if any Brnchid larva could 

 pierce them. Eggs of Bruclius pruininus laid on the seeds 

 of the latter species hatched properly but could not penetrate 

 into the cotyledon, perishing before they had pierced the seed 

 coat. They could not, likewise, penetrate the tough seed coat 

 of Acacia farnesiana. 



Within the seed coat of many leguminous seeds is an al- 

 bumen which is very hard and tough when dry and this may 

 serve as a sufficient barrier to prevent the further entrance of 

 the larva. The seeds of Cassia glauca resemble the seeds of 

 Leucaena glauca and Bruclius pruininus deposits its eggs upon 

 them freely both in the field and in captivity. The seed coat 

 is, however, harder and there is a layer of albumen within 

 that. The bruclius larva is able to pierce the seed coat but 

 perishes on its way through the albumen. 



Seeds, not otherwise defended from bruchus attack, may" 

 be unfit for the food of the bruchus attacking it and the larva 

 may perish as the result of feeding on the substance of the 

 cotyledons. 



Leguminous seeds vary greatly in their composition but 

 appear to agi-ee in having similar proteids which, as a group, 

 differ from the proteids of other seeds, being said to resemble 

 animal proteids more than those of gi-ains or oil seeds. Their 

 proteids are mostly globulins and the globulins of different 

 species of edible legumes are by no means identical. Thus the 

 phaseolin of the common bean is distinctly different from the 

 legumin and vicilin of vetches, broad beans, lentils, and peas 

 and it is not imi)robablc that the inability of bruchids to breed 

 in legiimes otherwise similar in composition to their host seeds 

 may be due to the diversity of ther proteids. The seeds of 

 many legimies, particularly the greater part of the edible le- 

 gumes, contain more than half their dry weight of starch, 



