27 



trypanosomiasis exists in Paraguay. It may be remembered that 

 this disease remained unnoticed for a long time in Brazil. Trypano- 

 soma equinum, infesting horses and mules, is distributed over a wide 

 area of the territory through which the expedition passed. American 

 leishmaniasis, locally called Baurii ulcer, and its causative agent, 

 Leishnania brasiUensis, are well known in the north-west of Sao Paulo 

 and in Paraguay. Tertian malaria occurred, but no cases were met 

 with of infection with the quartan form. 



Eckstein (F.). Die Ueberwinterung unserer Stechmucken. [The 

 Hibernation of our Mosquitos."] — Biol. Zentralhlatt, Leipzic, 

 xxxviii, no. 12, 23rd January 1919, pp. 530-536. 



In this paper on German mosquitos [R.A.E., B, vi, 211 ; vii, 69, 173], 

 it is stated that the details of hibernation in Germany have 

 not yet been fully investigated. All observers are agreed that the 

 males perish in autumn, the eggs, larvae and adult females being the 

 forms in which hibernation may occur. One or other of these is usual 

 in a given species ; for instance, in the case of Ctdex pipiens, it is the 

 adult female that hibernates as a rule. 



In the course of observations made at and around Strassburg 

 during the past few years, it Avas found that Anopheles maculipennis 

 generally hibernates in the adult stage, though it is possible that some 

 larvae may survive the winter. The females choose a dry situation 

 protected against wind, and do not seem to be influenced by light. 

 They bite in February after being kept in a warm room for some time. 

 On leaving their winter quarters they seek stables and sheds where 

 they can ol3tain a feed prior to oviposition. Under normal conditions 

 A. hifurcatus hibernates in the larval stage exclusively and no adults 

 have been found in winter. The larvae were found among leaves 

 at the bottom of subsoil-water holes or at the edges of large swamps. 

 They were also taken from partly-frozen puddles ; on one occasion 

 the temperature of the water was 37° F. (3-5° C). Nothing definite 

 can be said regarding A. p)lumheus (nigripes), but it probably over- 

 winters as an adult. 



Both Culex pipiens and Tlieobaldia (CuUseta) annulata are recorded 

 as hibernating in the adult stage. They choose damp situations 

 protected against wind and readily bite in January after being kept 

 in a warm place for some time. T. (CuUseta) fjlaphyroptera, Scliiner, 

 and Culex hortensis, Fie. {territans, Wlk.) are somewhat rare species 

 that overwinter in the adult stage. Schneider has stated that 

 T. {Cidieella) morsitans, Theo., does not hibernate as a larva, but the 

 author finds the contrary to be the case, at least in the woods around 

 Strassburg. Tfiis species appears to have one annual generation. 

 The imagines of Taeniorhi/nchus (Mansonia) richiardii, Fie, are found 

 singly in the w^oods near deep water in old stream beds and the larvae 

 hibernate at the bottom of such water. Aedes cinereus, Meig., 

 OcMerotatus (Culicada) nemorosus, Meig., 0. (C.) nigrinus, Eckst., 

 0. (C.) diversus, Theo., 0. geniculatus, Oliv. {C. lateralis, Meig.), 

 0. (C.) ornatiis, Meig., 0. (C.) dorsalis, Meig., 0. (C.) vexans, Meig., 

 and Cidex cantans, Meig., all occur near Strassburg and hibernate 

 in the egg-stage. 



