C26 Div. 3. ARTICULATA.— INSECTA. Class 3. 



it being only the females which bite.] The alulets generally cover the halteres ; the abdomen is de- 

 pressed and triangular ; the tarsi have three pulvilli. 



These insects appear towards the end of spring, and are very common in woods and pastures, flying 

 with a buzzing noise. They even attack man, to suck his blood ; and cattle in some parts are some- 

 times nearly covered with blood from the continued attacks of these insects. That of whicli Bruce 

 has spoken in his Travels, under the name of Tsaltsalyia, and of which even the lion is afraid, is prob- 

 ably a species of this genus. 



Pangonla, Latr. (Tanyglossa, Meig.), has the proboscis much longer than the head, slender, scaly, generally 

 pointed at tip, and with very short palpi : the last joint of the antennae is divided into eight rings. The species 

 are only found in hot climates, and subsist on the honey of flowers. 



The rest have the proboscis shorter, or scarcely longer than the head ; membranous ; terminated by two large 

 lips, and with the palpi at least equal to half the length of the proboscis ; the last joint of the antennae is divided 

 into five or four rings. 



Tahanus proper, has the antennae scarcely longer than the head; the last joint is rather crescent-shaped, and 

 divided into live rings, the first largest, with a tooth above. T. bovinus, De Geer, the Large Gad-fly, the larva of 

 which lives in the ground : it is longand cylindric, narrowed towards the head, which is armed with two hooks ; 

 the pupa is naked, nearly cylindric, with two tubercles in front ; the segments of the abdomen ciliated ; and si.\ 

 points at its posterior extremity. 



Tabanus maroccamis, Fabr., according to Desfontaines, attacks camels, which are sometimes covered with them. 



The others have the antenna; evidently longer than the head, and terminated by a joint of an elongate-conic form, 

 or nearly cylindric ; and generally only with four annuli. The ocelli are wanting in many. 



Silvius, Meig., has three ocelli, and the first joint of the antenna; is longer than the following, and cylindric. 



Chnjsops, possesses three ocelli, but the two basal joints of the antennae are nearly of equal length. C. dccittiens, 

 Fabr., a common species, which greatly torments horses. 



Jlijematojjota, Meig., w'ants ocelli, and the basal joint of the antenna; is thick, and nearly oval in the males. 



Ilexatovia, Meig. (Ileptatoma, previously), has the antennae larger than the preceding, and cylindric, with the last 

 joint very long; ocelli wanting. 



THE FOURTH FAMILY OF THE DIPTERA,— 



The Notacantha, — 

 lias, like the last, the third and last joint of the antennae transversely annulated, or composed of five 

 distinct joints {Chiromyzd) ; the sucker is formed of only four pieces ; the proboscis, of wliicli the stem 

 is very short, is nearly withdrawn into the oral cavity : tlie membranous consistence of this org.an, and 

 its reflexed lips ; its clubbed palpi, also reflexed ; the arrangement of the wings, which are mostly crossed 

 over each otlier ; the oval or orbicular form of the abdomen ; and the scutellura often armed witli 

 points, distinguish the Notacantlia from tlie Tabanides. But few of their larvae have been observed: 

 tliose hitlierto observed, and whicli have been described by Swammerdam, Reaumur, and Rosel, are 

 aquatic (see below), and approach those of the Athericera by their soft head of a variable form, [.'] and 

 by their habit of changing to pupoe beneath their own skins ; but they preserve tlieir former size and 

 form, wiiicli is not tlie case witli tlie Athericera. The larvaj of oilier Notacantha {Xtjlophagus), live in 

 the rotten and moist parts of trees. 



We divide the Notacantha into tlirce principal sections, [Mi/dasii, Decatoma, and Stratiomydes]. 



The first, jMydasii, have no teeth or spines on the scutcllum ; the body is oldong, witli tlie abdomen 

 long, triangular, and conical ; the wings are extended ; tlie antenna;, wliich constitute the chief 

 character, arc composed either of five distinct joints, two of which firm in some a club, and in others 

 the extremity of a cylindrical stem ; or of three joints, the last of which is largest, nearly cylindrical, 

 gradually pointed, and divided into three annuli ; so that these organs are always divided into five. 

 If we excciit Mydas. in wliich we have the rudiments of a style, neither the latter nor the seta exists 

 in any of these Notacantha; ; jjiobably the two terminal joints rejiresent them. 



Some have the antenna; much longer than the head, 5-jointcd, terminated in an elongate mass formed of tl;c 

 last two joints, with a very short teiniinal seta ; the hind tliighs are strong, and toothed or spiny beneath. The 

 tarsi have only two pulvilli. The posterior cells are closed before reaching the apex of the wing. These Diptera 

 compose the genus 



Mydas,— 

 "Which is divisible into two subgenera. 



Cep/ntluceia, Latr., has the proboscis long, and advanced. 

 Mi/(Ias proi)er, Inis it short, and terminated by two large iips. 



Others have the antenna; scarcely longer than tlie bead, and cylindric; the t.irsi hove three pulvilli, and tha 

 posterior cells extend to the hind margins of the wing":. 



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