It is often more convenient to call an insect hy its common name than by its scientific name. This doubtless is the case with Microcephalothrips abdominalis (Crawford). Watson (1923) first referred to this thrips as the “Compositae Thrips” and, in view of its decided preference for members of this plant family, it seems appropriate to adopt this common name.

Male (type) resembles H. ziziae (Rob.), to which it runs in my table and that of Metz (but in Lovell's table to modestus), differing however as follows: lateral face marks obliquely truncate above, the highest point next to orbit; flagellum considerably longer, pale dusky reddish (instead of bright ferruginous) beneath; tegulae entirely black; base of wings not pale; thorax more robust, light marks on collar separated by an interval greater than the length of one; wings larger, grey, with the stigma and nervures very dark; abdomen shining pure black (compared with an Illinois specimen from Robertson.).

In the course of revising the subfamily Cuculliinae of the Noctuidae, it has become obvious that many of the species have been placed in genera where they do not belong, and others have been merely “dumped” into the most convenient genus; it is to rectify the above conditions that the following genera are described.

Except for one species described by Cresson as Cteniscus californicus, but apparently referable to this genus, all the known American species occur in Canada. A study of the material contained in the National Collection has revealed several species which appear to be new. Descriptions of these are given below together with notes on the previously described species and a key is provided for the separation of all species except californicus. According to the original description of californicus it differs from the species here treated in having the mesoscutum prominently marked with two reddish longitudinal stripes.

In 1935 some notes were published on the heredity of striping in 1st instar larvae of Tropaea luna. The majority of the material obtained up to 1936 gave a 1-1 ratio of striped and unstriped larvae when the character appeared. The exception was a whole brood of striped larvae.

The specimens upon which this paper is based were received from various parts of four Western States. Those of the first lot were from South Dakota and were sent to the writer by Prof. H. C. Severin of Brookings, S. Dak. Among these was one specimen labeled “Rivellia sp. n.?” by the late Dr. J. M. Aldrich. Later, other specimens were received from H. E. Jaques, Iowa; C. W. Sabrosky, Kansas; Maurice James, Colorado; and one specimen from North Dakota, received from C. E. Mickel.