38 



book. The sources, however, of many of the numerous excellent 

 illustrations are given ; those that are not original have been selected 

 from well-known manuals, and this careful selection enhances the value 

 of this up-to-date, but not too technical, entomological primer. 

 Unfortunately the index does not include the insects that are illustrated, 

 but not mentioned in the text. 



Martini (E.). Zur Bionomie unserer Stechmiicken. [A Contribution 

 to the Bionomics of German Mosquitos.] — Arch. Schiffs- u. Trop.- 

 Hyg., Leipsic, xxv, no. 11, November 1921, pp. 341-347. 



The results of a series of breeding experiments with mosquitos fed 

 on " Piscidin " are tabulated. In the case of Anopheles bifurcatus, 

 A. macidipennis and Theohaldia annulata the duration of the egg- 

 stage, of each of the four larval stages and of the pupal stage is shown. 

 For A. bifurcatus the total period ranged from 16| days to 19 davs 

 at 24°-26° C. [75°-79° F.] ; at 20°-22° C. [68°-72° F.] from 17* to 

 30 days were required. For A. macidipennis at 24°-27° C. [75°- 

 81° F.] the time was 13^-16 days, these figures including an egg stage 

 of doubtful duration (? 2 days) ; at 20°-22°C. [68°-72° F.] 16-20 days ; 

 and at 16°-19° C. [61°-66° F.] 27-35| days. For T. annulata at 

 24°-27°C. [75°-81°F.] the time was 16* days; at 20°-23° C. 

 [68°-73°F.] 17-19 days; at 16°-20° C. [61°-68° F.] 21-26 days. 

 The course of development is generally more regular at the higher 

 temperatures. In all cases the fourth larval stage lasts longer than the 

 other three. Males develop more quickly than females. 



It is not known whether the minimum time of development is shown 

 in these tables. Feeding was done three times a day, but as no traces 

 of food were seen in the morning it is possible that the quantity was 

 not sufficient, thereby prolonging development by one day. In the 

 case of T. annulata it is certain that the time could be reduced by a 

 different method of feeding. Higher temperatures did not pro^'e 

 successful. The figures for T. annidata at 27° C. [81° F.] show that 

 constant temperatures as high as this are unsatisfactory (in 

 further experiments it was also difficult to obtain a pupa and adult 

 from a fourth-stage larva of Aedes rusticus {diversus) at this tem- 

 perature). At a lasting temperature of 30° C. [86° F.] it was difficult 

 to breed A . macidipennis, and the few adults obtained showed a slight 

 prolongation of development. For this species, therefore, 27°-28^' C. 

 [about 81° F.] may perhaps be the optimum as far as constant 

 temperatures are concerned. 



These results agree well with those of Howard, Dyar and Knab, 

 Ziemann, and Sella [R.A.E., B, viii, 222]. It is possible that tne 

 smaller Anophelines can develop somewhat more rapidly. 



The eggs of Aedes nigripes usually hatch 6-8 hours after wetting. 

 In summer at a temperature of 2r-24° C. [70°-75° F.] the larval stage 

 lasts about eight days ; the pupal stage requires onl}^ about three 

 days. These periods are probably shorter in nature, and as the 

 adults can emerge from the pupae on damp ground, it is sufficient for 

 a collection of water to remain for about eight days to give rise 

 to a brood of this species. 



In testing the resistance of Anopheline larvae to cold, the eggs of 

 A. macidipennis were found to remain uninjured on damp (not wet) 

 frozen earth for several days. It is, therefore, possible that Anophelines 

 that have matured their eggs indoors in winter may oviposit outdoors 



