INSECT NOTES. 223 



22.) The head and thorax have clearly denned marks of 

 deep orange yellow, along the posterior margin of each abdom- 

 inal segment is a narrow but distinct line of the same color, and 

 the wings near the body are clouded also with orange. The 

 expanse of wings averaged about 2 and one-half inches. The 

 species was kindly determined by Mr. Heidemann as Tibicen 

 rimosa Say, var: noveboracensis Fitch. 



Diamond-back Moth, Plutella cruciferarum, as a Greenhouse 

 Pest. Early in April a complaint came from a greenhouse in 

 Ellsworth of a small green caterpillar which destroyed ten 

 weeks stocks, working on leaves and flowers. Specimens were 

 received with the communication and were bred to the adult 

 stage, part of them proving to be the light form and part the 

 dark form of the Diamond-back. On May 24, a new lot of 

 these larvae were received from the same source again at work 

 upon the stocks. This species, described with reference to 

 materials bred on stocks in greenhouse, is as follows : 



The caterpillars when full grown are three-eighths of an inch 

 in length. The color is a light green with the head concolorous 

 or sometimes shading to yellowish. The median dorsal line is 

 a more vivid green. To the naked eye they appear smooth, but 

 a low power glass reveals stiff dark hairs rising from lighter 

 spots arranged in a regular manner upon the segments, These 

 hairs are most numerous upon the last thoracic segment. The 

 last pair of abdominal pro-legs are extended back horizontally 

 giving the body a forked appearance. The pupal stage is 

 passed within a very delicate white, gauzy cocoon through which 

 the pupa is readily seen. Some of the specimens reared passed 

 but 6 days in the pupal stage. 



The perfect insect is a moth expanding about five-eighths of 

 an inch. The fore wing is ash colored with minute dark spots 

 upon it. A yellowish stripe outlined with a dark line extends 

 along the hinder margin in such a manner that when the wings 

 are closed, 3 light colored diamond shaped markings are formed. 

 Both pairs of wings are a uniform gray on the under side. The 

 antennae are marked with alternate rings of white and dark. 



The Diamond-back is an imported moth and it occurs fre- 

 quently upon cabbage and cauliflower in the garden. Doctor 

 Fletcher reports * the Diamond-back to be an incessant and 

 most troublesome pest upon garden stocks and -wall-flowers 



* Can. Exp. Farms 1890, p. 165. 



