6 HENRY F. CARTER. 



Head. Eyes bare, widely separate (the space between them varying from one-fifth 

 to almost one-half the width of the head) in both sexes.* Vertex and occiput bearing 

 a few short hairs or bristles ; frons nude or with at most a single pair of short bristles 

 between the eyes (fig. \,h). Clypeus moderately pronounced, rounded, hairy. 



Proboscis as long as, or rather less in length than, the height of the head. Mouth- 

 parts in the female as follows : labium soft and hairy, broad, the labella relatively 

 large ; labrum strongly chitinised, broad at the base, gradually tapering towards a 

 rounded apex, the extremity armed with three recurved teeth ; hypopharynx less 

 strongly chitinised than, but somewhat similar in shape to, the labrum, the apex 

 devoid of teeth, pointed and scoop-like ; mandibles and maxillaef well-developed, 

 the former moderately chitinised, relatively broad and obliquely truncate or curved 

 distally, bearing twelve to twenty-four small, closely apposed teeth, the maxillae 

 narrower, slightly shorter and more pointed, armed with from twelve to thirty larger 

 and more widely separated teeth. Mouth-parts in the male less strongly chitinised 

 than those of the female ; extremity of the labrum hairy, mandibles not visible 

 (? absent) in the single specimen available, maxillae slender, thinly chitinised, 

 pointed, without teeth. 



Fig. 2. Palpi of O 9 of : {a) L. stygius, Sk. ; (h) L. torrens, Twns. ; [c) L. rhodesiensis, sp. n. ; 

 (d) L. kerteszi var. americanus, n. ; [e) A. spiiiosi frons, sp. n. ; (/) L. siamensis, sp. n. ( X 220 circa). 



Palpi (fig. 2) composed of four segments. In the female the first and second 

 segments are reduced in size and often indistinctly separated one from another, the 

 third incrassate, the last relatively large, representing the combined small fourth and 

 fifth segments of other Ceratopogoninae ; the sensory pit of the third segment is 

 highly developed, the orifice often large, occupying the greater portion of the inner 

 aspect, or occasionally small, sub-circular ; terminal segment with an apical whorl of 

 hairs. In the male the palpi are longer than in tlie female, and the third .segment is 

 not, or scarcely, swollen. 



* In this account remarks concerning male characters are based upon the examination of a 

 specimen provisionally referred to L. torrens (see p. 15) and Noe's description of L. bezzii. The 

 male of L. kerteszi {M. laurae, Weiss) is not considered here, since, as shown on p. 22, its structure 

 in certain respects is so peculiar that confirmation of Weiss's observations is desirable before any 

 definite statements can be made. 



t Langeron (1913) in his description and figure of the mouth-parts of the female of L. kerteszi 

 var. peveti (M. laurae var. peneti) has, through incorrect interpretation, transposed the names of 

 these structures. 



