179 



caustic soda 30 lb., carbolic acid 150 gals., has been successfully- 

 used as a substitute for the more expensive kerosene. It emulsifies 

 readily in water, but unfortunately cannot be used in brackish and 

 alkaline waters as they neutralise it. 



The SiMULHDAE are chiefly represented by the abundant species, 

 Simulimn similis, Mall., which is capable of causing extensive losses 

 among live-stock, 100 head of cattle having died from its attacks in 

 one locality in J 913. The first swarms generally appear about June, 

 though infestations may recur as late as September and October. 

 The eggs are laid on the exposed surfaces of stones or weeds in the 

 rapids of streams and rivers. The whole life-history occupies about 

 six weeks. 



At present the only measure of control is to burn smudges, the 

 dense smoke from which protects the cattle, or to dress their coats 

 with a repellent such as fish-oil, or a mixtiu-e of three parts fish-oil and 

 one part kerosene, which should be renewed once a day during the 

 season. The destruction of the larvae by toxic substances in streams 

 and rivers is impossible, owing to the danger to stock and human 

 beings, and to the fact that the fish are thereby killed. 



Of the Tabanidae the most commonly occurring species is Tahanus 

 septentrionalis, Lw. ; other species are T. illotus, O.S., T. hirtulus, Big., 

 T. phaenofs, O.S., T. rhomhicus, O.S., T. captonis, Marten, and 

 T. eristatus [? epistates, O.S.]. None of these are troublesome to 

 human beings, but are persistent in their attacks on grazing cattle and 

 horses. Working horses may be amply protected by the use of fly 

 nets. Chrysops moerens, Wlk., and C. fulvaster, O.S., are common 

 round sloughs in summer, attacking human beings when disturbed. 

 Haematopota americana, O.S. (breeze fly) is occasionally found round 

 horses and readily settles on human beings. 



Horses may be protected from those flies that attack the ears by 

 the use of nets, and from those attacking the eyes by smearing the 

 skin round the eyes and ears with a repellent composed of pine-tar 

 1 gal., kerosene, fish-oil or crude carbolic acid 1 qt., powdered 

 sulphur 2 lb. ; a mixture that may also be applied to wounds to prevent 

 oviposition therein. The method of destroying the adults by oiling 

 their drinking pools has already been dealt vdth [see this Review, 

 Ser. B, iii, pp. 195-196]. 



Van Zwaluwenburg (R. H.). Report of the Entomologist. — RepL 

 Porto Rico Agric. Expt. Sta. for 1916, Mayaguez, 5th February 

 1918, pp. 25-28. [Received 15th July 1918.] 



Two varieties of ticks infest cattle in Porto Rico, Margaropus 

 annulakis australis and M. annidatus, the latter being present in 

 much smaller numbers than the former. M. annidatus a.nstralis 

 requires from 20 to 22 days for its development on the host during 

 the autumn months. Hence if local eradication of the tick is to be 

 attempted, applications of dips, sprays or smears should be renewed 

 about every three weeks to prevent the maturing of fresh generations. 



The minimum length of the egg period under natural conditions 

 was found to range from 36 days in February to 23| days in September. 

 The maximum starvation period of ticks hatching in April was found 



