MEGARHINUS 929 



Genebic Diagnosis of Larva: 



Head rounded subquadrate, slightly longer than wide, not widened laterally, pro- 

 duced in front into two stout conical lobes which bear the mouth -brushes; eyes 

 inconspicuous. Antennae small, slender, smooth, the small hair tuft situated near 

 the tip. Mouth parts modified for the predaceous habit; mouth brushes a series of 

 ten large chitinous lamellae, hooked at the ends, inserted beneath apices of anterior 

 lobes and folded together; mandibles dentate; maxillae broadly quadrate. Thorax 

 flattened, circular, the lateral hairs few, short, thick and inserted on chitinous 

 tubercles. Abdominal segments laterally angularly expanded, with abundant hairs, 

 the lateral tufts inserted on small chitinous plates. No lateral comb on the eighth 

 segment, but a chitinous plate. Air tube moderate or short, smooth, without pecten, 

 a single pair of hair tufts situated towards the base. Anal segment short, ringed by 

 a chitinous band with posterior fringe of spines; ventral brush well developed, con- 

 fined to barred area. Anal gills generally very short and equal. Some of the body 

 hairs very much thickened and spinulose. The color of the body is more or less of a 

 dull dark crimson. In some species the skin shows iridescent colors. 



Tropics of both hemispheres, particularly in forested regions. In North 

 America one species penetrates northward along the Atlantic coast and up the 

 Mississippi valley. 



There are three divisions of the genus of perhaps subgeneric value indicated 

 by differences in the palpi of the female and conditioned by geographical areas. 

 Megarhinus proper, with the palpi of the female long and blunt, inhabits 

 America, being best developed in the tropics and giving rise to Ankylorhynchus, 

 which has the palpi long and acuminate in both sexes, in the southern part of 

 that area; Worcesteria, with the palpi of the female short, is the Old World 

 development, well represented in the Indo- Australian region. 



The species were at first included under Culex, but very early recognized as 

 distinct, the term Megarhinus being proposed by Eobineau-Desvoidy as early 

 as 1837. Practically all subsequent authors have accepted this genus, which has 

 only lately been divided on differences in the palpi in one or the other sex, 

 Theobald proposing Toxorhynchites in 1901 for Old World forms with the palpi 

 of the female short and Lutz proposing Ankylorhynchus in 1904 for South 

 American forms with the palpi of the female acuminate, as in the male. Theo- 

 bald intended Toxorhynchites for the Old World species, but Howard first pub- 

 lished the name, mentioning only the American Megarhinus rutila Coquillett, 

 which thus becomes the type and makes the name strictly synonymous with 

 Megarhinus. The use of Toxorhynchites by Theobald and others for the Old 

 World species is therefore erroneous. If it be desired to designate the forms 

 with short palpi by a separate name, Worcesteria Banks is available. These 

 divisions are based on too trifling characters to be recognized as valid genera, 

 and the names can only be recognized for subgeneric groups. The genus is a 

 decidedly specialized one. It was raised to subfamily rank, by Theobald in 

 1901 (Mon. Culic, i, 215), a course unquestioningly adopted by most subse- 

 quent authors. Later, the genus Toxorhynchites was independently made a 

 separate subfamily by Lahille in 1904 (Toxorhynchina, Actas y Trab. 2 Congr. 

 Latino-Amer., ii, 11, 16) and Theobald in 1905 (Toxorhynchitinae, Gen. Ins., 

 Dipt. 26 fasc, 13) . Furthermore the names Ankylorhynchae and Megarhininae 

 were introduced by Lutz (Bourroul, Mosq. do Brasil, 53, 1904) and Lynchiel- 

 lina by Lahille (Actas y Trab. 2 Congr, Med. Latino-Amer., ii, 11, 13, 1904). 

 These names are only a transitory expression of the general over-valuation of 

 characters in the Culicidae, which has arisen in the minds of uncritical writers 

 following the remarkable attention that these insects have received since their 

 role in the transmission of disease has been discovered. 



The species of Megarhinus are, so far as known, exclusively predaceous in the 

 larval state. They inhabit water in hollow trees, broken bamboos or leaves of 

 bromeliaceous plants and feed upon the larvae of such other species of mosquitoes 



