INSECT RECORD 1T5 



covered with Anthomyia larvae. On looking for other 

 mustard plants I was surprised to find them very scarce, 

 and I realized that the ground^ which recently came into 

 my possession completely stocked with the seeds of wild 

 mustard, had grown this season very few of these plants. 

 In previous seasons they have sprung up by thousands. 

 It was evident also that it was not a case where the plants 

 had started and been killed by Anthomyians; the plants 

 had not come up at all. And the reason was not far to 

 seek. In early spring, when the wild mustard usually 

 starts, we had an extraordinary drouth which prevented 

 the germination, not only of the seeds planted by the gar- 

 dener, but also those planted by nature. Of the last the 

 wild mustard is a conspicuous example. 



Further observations and inquiries led me to this tenta- 

 tive conclusion : 



That usually the wild mustard and allied cruciferous 

 species act as natural trap plants for the eggs of the An- 

 thomyians, germinating abundantly earlier than do culti- 

 vated crops, and that this year the failure of the natural 

 trap plants compelled the flies to wait for oviposition until 

 the cultivated plants were ready, thus leading to the extra- 

 ordinary attack upon them. 



These Anthomyians are so difficult to combat that it 

 seems to me this suggestion is at least worth further con- 

 sideration in the way of observation and experiment. 



During late summer and early autumn, the Zebra Cater- 

 pillar attracted much attention from owners of gardens. 

 This is a caterpillar with curious black and yellow mark- 

 ings upon its body. It hatches from eggs laid upon the 

 leaves of cabbage and other plants by a purplish brown 

 moth. At first, the larv^ are very dark and feed together 

 in colonies, but as they grow older they become lighter in 

 color and disperse over the plant. When disturbed, they 

 curl up and drop to the ground. They become full grown 

 in a few weeks, when they are about two inches long, with 



