1917J ENTOMOLOGY. 553 



'Celery to an average depth of t^ in. While the work of a single larva does not 

 extend for more than about i in. between two of the vascular ridges, a large 

 number swarm around infested plants so that the whole of the portion of the 

 plant below the ground, some 9 in. in length, may be affected. Rarely larvae 

 ■burrow deeply into the pulp, thus forming small tunnels. In a typically at- 

 tacked plant five of the largest stalks were seriously damaged and three to a 

 lesser extent, the central stems not being damaged. 



The attacked areas turn brown during the late summer and autumn, and are 

 the seat of infection for various fungus diseases and small dipterous larvae, 

 such as Drosophila, which soon render the plants unfit for the market. Since 

 the damage is to a large extent incidental to the method of bleaching celery by 

 bringing it into contact with larvge-infested earth, it is recommended that in 

 localities where these larvae occur in large numbers the celery be bleached 

 between boards or prepared paper. 



What is Tabanus mexicanus? F. Knab (Insecutor Inscitm Menstruus, 4 

 (1916), A'o. 7-9, pp. 95-100, fig. 1). 



Two new North American Diptera, R. C. Shannon {Insecutor Inscitiw Men- 

 struus, Jf {1916), No. 4-6", pp. 69-12, fig. 1). 



Critical notes on Syrphidae, F. Knab {Insecutor InsciticB Menstruus, J, {1916), 

 No. 7-9, pp. 91-95). 



Further notes on Sjrrphidse, F. Knab {Insecutor Inscitice Menstruus, 4 {1916), 

 No. 10-12, pp. 133-135). 



Notes concerning Gastrophilus hsemorrhoidalis, R. R. Pabker {Jour. N. Y. 

 Ent. Soc, 24 {1916), No. 4, PP- 253-255. fig. i).— Observations of the peculiar 

 shape of the egg of the nose fly or red-talleil hot {G. hcemorrhoidalis) have 

 led the author to suggest that the pain which results when the egg is thrust 

 into the nose or lips of a horse may account for the nervous and sometimes 

 uncontrollable fear shown by the horse when the flies are •' striking." 



Lithohypoderma, a new fossil genus of oestrids, C. H. T. Town send {Insecu- 

 tor Inscitiw Menstruum, 4 {1916), No. 10-12, pp. 128-130). 



Some notes concerning overwintering of the house fly, Musca domestica, 

 at Dallas, Texas, W. E. Dove {Jour. Econ. Ent., 9 {1916), No. 6, pp. 528-538). — 

 The observations here reported, all of which were made at Dallas, Tex., have 

 been summarized by the author as follows : 



"Adult house flies having sufficient food, not subjected to fatal temperatures, 

 killed by Empusa mtiscce, nor destroyed by predators, show increased longevity 

 in indirect proportion to decreases in temperature. The general tendency of 

 adults to seek temperatures above 60° F. necessarily causes a shorter longevity 

 than 91 days, which was obtained in a most favorable abnormal caged condi- 

 tion. The humidity being normal and adults being prevented from warmer tem- 

 peratures, they become inactive at 45°, crawl slightly at 48°, and will volun- 

 tarily fly at 53°. Even previously fed adults, if subjected to freezing tempera- 

 tures, die in less than three days. ' Northers,' causing sudden drops in tempera- 

 ture, are responsible for a large mortality of flies in the vicinity of Dallas, Tex., 

 yet warm periods occur during midwinter which permit depositing. 



" There is a possibility that epidemics of E. musc<B may be caused by a lack 

 of deposition media for flies which are sexually matured and have copulated. 

 Breeding media ranging from 46 to 55° in 12 hours will permit emergence of 

 adults from puparia, but emergence has never been observed at lower tem- 

 peratures. Great numbers of pupae near the surface of the soil receive either 

 enough heat to permit emergence of adults, which usually succumb to cold 

 before depositing or the temperatures are so low that they become inviable. 

 Young larvae have been kept for more than 67 days without pupating, but only 

 85476°— No. 6—17 ^5 



