246 MAJOR W. S. PATTON 



2. Subfamily Oestrinae. 



This subfamily has recently been monographed by Rodhain and Bequaert, who 

 recognise five genera. The larvae of Oestrus, Gedoelstia and Kirkioestriis are para- 

 sitic in the frontal and neighbouring sinuses of ruminants, those of Rhinoestms in 

 the same sinuses of equines,"pigs and the hippopotamus ; and the larvae of Cephalop- 

 sis {Cephalomyia) in the naso-pharynx of the dromedary and camel. 



The following key is taken from Rodhain and Bequaert, and may be found 

 useful in distinguishing the genera : — 



1 {a) Wings with a section of the apical transverse nerve (the outer 

 section of the 4th nerve ?) turned up almost vertically to the long 

 diameter of the wing. Long veins 2, 3 and 4 almost of the same 

 length, ending before the last quarter of the wing. Transverse 

 marginal vein ending before the middle of the first posterior marginal 

 cell. Antennal pits separated on the face by a large flattened 

 border . . . . . . • . • • • • • • Cephalopsis. 



1 (b) Transverse apical vein not vertical to the long diameter of the wing. 



Transverse marginal vein ends in the middle of first posterior cell or 

 thereabouts . . . • • • • • • • • • • • . . 2. 



2 (a) Rudiments of proboscis elongated, prolonged in front towards the end 



between the palps, the extremity divided into three long cushions 

 which represent the labella and the rudimentary lips. Antennal pits 

 more or less confluent, but separated by aflattened round ridge. Body 

 thick-set, covered with large papules. Abdomen short, cylindrical, 

 almost without pilosity. Legs short and slender. Apical transverse 

 nerve without an appendix Rhinoestms. 



2 (b) Rudiments of proboscis conical, not extending beyond the palps at the 



base, and without traces of labellae. Venter and posterior extremity 



of abdomen covered with long and fine pilosity . . . . . . 3. 



3 (a) Antennal pits confluent, not separated by a median flattened edge. 



Abdomen elongated, slightly flattened dorso-ventrally, contracted 

 and bent towards the base in'front. Body without papules and gross 

 sculpture, but with short abundant pilosity, especially on abdomen ; 

 relatively long and robust. Apical transverse vein with an 

 appendix . . . . . . . . • • • • • • Kirkioestrus. 



3 (6) Abdomen squat, cylindrical, not flattened dorso-ventrally, not recurved 



towards the front. Body grossly sculptured, either with tufts or 

 papules, less on thorax. Pilosity not very abundant. Short and 

 slender legs. Apical transverse vein without an appendix . . 4. 



4 (a) Antennal pits not confluent, separated on face by a large flattened edge. 



Abdomen with denticulated tufts on dorsal surface of segments 2, 3 

 and 4 . . . . . . • • • • • • • • • • Gedoelstia. 



4 {b) Antennal pits more or less confluent, not separated by a large flattened 



ridge. Abdomen without any tufts on the dorsal surface. . . Oestrus. 

 The following notes on the species give the hosts in which the larvae are found : — 

 Oestrus ovis, L. — The common sheep and goat bot, found wherever the hosts 

 occur. Its larvae are parasitic in the nasal passages, and are often present in large 

 numbers. Although the larvae are easily obtained, the adults are seldom seen. 

 The first stage larva has been recorded from man in Russia, Italy, and Algeria, in 

 the conjunctiva, mouth and nasal cavities ; but it is more than probable that in the 

 majority of these cases they were not those of 0. ovis but of Rhinoestrus purpureus. 



Oestrus variolus, Lw. — This is the common bot of the western hartebeest, Bubalis 

 major, and Jackson's race of the Lelwel hartebeest ; its larvae are found in the nasal 

 passages of a large percentage of these antelopes. 



