1918.] ECONOMIC ZOOLOGY ENTOMOLOGY. 763 



by a single female in captivity was 110, deposited in four lots. The duration of 

 the egg stage averaged about 19 days, with variations from 15 to 38 days. 



The natural enemies of the changa in Porto Rico are ineffective, an unde- 

 termined nematode being the single parasite that atta(;^s it, though the fungus 

 Metarrhizium anisopliw is thought to have killed some in the breeding cage. 

 During the fall months the changa flies in large numbers on damp overcast 

 evenings at which time the females in particular are attracted to light. Flood- 

 ing is of value in control work wherever the location of fields makes water 

 easily available as changa eggs fail to survive a submergence of 24 hours. 

 Naphthalin and sulphur are the only repellents found to be of any value, and 

 even they are only partially effective. Sugar cane is protected from the 

 changa by planting it in a perpendicular or slanting position, and hilling up the 

 plants greatly reduces injury by this pest in gardens. Poison baits, particularly 

 one consisting of cheap flour and Paris green, together with clean cultivation, 

 are recommended. 



A list of 54 references to the literature is appended. 



The citrus thrips, J. R. Hoeton ([7. S. Dept. Ayr. Bui. 616 (1918), pp. 42, 

 pis. S, figs. 10). — This is a summary of the present status of knowledge of 

 (Euthrips) Scirtothrips citri, based upon the author's investigations in Califor- 

 nia and a review of the literature, including earlier reports of the Bureau of 

 Entomology, prevously noted (E. S. R., 33, p. 354). The history and distribu- 

 tion of the citrus thrips, nature and extent of injury, dissemination, food plants, 

 life history and habits, seasonal history, natural checks, natural enemies, and 

 control experiments are considered and a bibliography of 16 titles appended. 



Plain lime-sulphur solution, 1 : 56 of the 36° B. density or 1 : .50 of the 33°, is 

 recommended as the most reliable of the four best mixtures resulting from the 

 tests, a soda-sulphur solution being the next most effective mixture. The first 

 application should be made when four-fifths or more of the petals have fallen, 

 at which time the orange is most susceptible to deep injury by the thrips. The 

 second application should be timed to prevent injury both from larvye issuing 

 from the very young fruits and from adults emerging from the pupal stage 

 existent at the time of the first application, i. e., from 10 to 14 days after the 

 first spraying. The time of application of the third spray depends upon the 

 effectiveness of the first two, it usually taking from three to four weeks for the 

 thrips to again become dangerously numerous. "All three applications should 

 be completed by the time the fruit is half grown, after which it rapidly loses 

 its attractiveness for the insects, which then find it necessary to spread out 

 over the comparatively scant tender orange growth and miscellaneous food 

 plants. 



" During the latter part of August and early in September there is usually 

 another abundant growth of orange shoots, and upon this the thrips congregate 

 in large numbers. A fourth application during this period is advisable in some 

 seasons to prevent severe injury to this growth, which is often the most abun- 

 dant of the season." 



On nursery stock the first application should be made when the thrips become 

 numerous on the spring growth and before their injury becomes very evident, 

 usually between April 15 and May 15. From two to four further applications 

 should follow the first spraying, depending upon the number of growths and 

 the degree of infestation. 



Catalogue of the Herniptera of America north of Mexico, excepting the 

 Aphididae, Coccid£e, and Aleui'odidae, E. P. Van Duzee (Vniv. Cal. Pubs. Ent., 

 2 {1911), i^'o. n, pp. XIV+902; rev. in Science, n. ser., 41 (1918), No. 12i2, 

 pp. 292. '293).— This catalogue undertakes to give a complete enumeraUon of 



