Vol. XXXl] ENTOMOLOGICAL NEWS 123 



The common cotton stainer of the Island seems to be 

 Dysdercus andreae L., which is much more frequently found 

 in the drier northwest and south coast sections, than along 

 the humid northeast and east coast. While the bug is some- 

 times locally abundant, it may at other times be entirely miss- 

 ing in a cotton field, so on the whole cannot be considered 

 a serious pest of the crop. 



During the past winter (December and January) the writer 

 has had opportunity to make a close study of the cotton in- 

 sects in a field on the Insular Experiment Station grounds at 

 Rio Piedras. Needless to say, the pink boll worm and boll 

 weevil have been entirely absent; and we have yet to discover 

 these two pests on the Island. It was a surprise, however, to 

 have found only two leaf caterpillars (Alabama argillacea 

 Hubn.) on the plants in the whole winter, in view of the fact 

 that Urena lobata has grown abundantly in the neighborhood 

 through the summer, and was subject to considerable attack. 

 The reduction of the pest may be accounted for by the pre- 

 vailing dampness of the weather in conjunction with some 

 disease. The common boll-worm has been another pest miss- 

 ing, although infected ears of corn have been found growing 

 very near the cotton. An occasional larva of the tropical 

 cutworm, Xylomiges sunia Guen., has been found attacking 

 foliage, but this may be considered accidental, as the larva 

 much prefers garden crops, amaranth and morning glory. 



The most injurious pest has been the greenhouse thrips, 

 Heliothrips haemorrhoidalis Burm. Larvae and adults gather 

 in some numbers on the outside of bolls, underneath the calyx, 

 where they scarify the surface and cause white scars that 

 later turn brown, and seem to be immediately concerned in 

 the attack of a disease that somewhat discolors the bolls and 

 causes the calyx to cement itself to the outside of the boll, 

 preventing the latter from bursting properly. The preced- 

 ing generation of this thrips was found in November attacking 

 the undersides of grapefruit leaves, where it occurred in all 

 stages and caused a considerable scarring, and some mal- 

 formation, of the foliage. A careful search for them on citrus, 

 in latter part of January, revealed only four adults and no 



