FAM. BLEPHAROCEKID.E 



mating or egg-laying, although many hours were spent in watching thern. They weie most numerous 

 on bright, sunshiny days ; on cloudy days the favorite rocks were often entirely deserted. The flight 

 is poor and numerous flies were caught readly in the hands. 



Schnuse found the Hies of both sexes oi Apistomia elcgans on composite flowers, sucking! But the 

 females were probably hunting small insects, not nectar or pollen. Scherfling and Bezzi have described 

 some of the habits of Hapalotherix liiguhis found on the southern slopes of the Alps in North Italy. Males 

 were seen flying in and out of the foam of a falls at the tongue of a glacier; no females were with them. 

 As soon as the shadow of the mountains reached the falls the flies dissappeared. When at rest the flies 

 sit on stones and cliff" walls near the stream with halt opened wings and raised hind body. Females 

 appeared to be in much smaller numbers than males. Various mating pairs resting on the water were 

 washed by the waves on to the banks and often drowned. Several species of Hilara were found 

 associated in flight with Hapalothrix individuals and served as prev for them. Hapalothrix was found 

 flving from the end of Mav to the end of August, depending somewhat on the altitude. 



For a satisfactory discussion of the feeding habits of these flies a knowledge of the anatomj^ of 

 the mouth parts is indispensable. The females of Blepharocera,like the females of Simuhum,Ceratopogon 

 Dixa, Culex, and some other Nematocera, are bloodsucking, and whilethe mouth parts of these forms are 

 not strictl}' of biting type the mandibles are present as cutting or sawing or piercing organs. The males 

 of these forms are nectar-feeding, and have lost the mandibles. In the mouth parts (pi. i, f. i3) of the 

 female Blepharocera all of the parts of the tj^pical biting mouth are present, namely, the mandibles, 

 maxillae and labium. The mandibles are long and serrate on their inner edges so as to be effective 

 lacerating instruments. The maxillae are elongate and blade-like, and have 4-segmented palpi. The 

 labium is, though somewhat elongated, truly lip-like, and has its terminal lobes not coalesced and 

 without pseudo-tracheae. The hypopharynx is not short and tongue-like, as in the orthopterous mouth, 

 but is long and slender and stylet-like. Altogether the difference between the mouth parts of Blepharocera 

 and the t3-pical biting type is one of modification, and of modification not sufficient to obscure the 

 homologies, although a modification more profound than that shown bv the most generalized Lepidoptera 

 or Hymenoptera. On the other hand, there is not much difiiculty in tracing the development of the 

 dipterous mouth from the generalized condition of Blepharocera (or Simulium, or Dixa, etal.)ioÛ\at extra- 

 ordinary specialized condition shown by Musca, where the mandibles and maxillae are lost, and the 

 labium is so modified that it has no longer any likeness to the lower lip of the orthopterous mouth. 



With regard to the curious condition of the e3-es of the adult Blepharocerids, the following is 

 taken from the account in the Entomological Na^'s (Kellogg. 1900) of the eyes oi Blepharocera capitata : 



« A specially interesting point in the imaginai anatomy of Blepharocera is the structural condition 

 of the compound eyes. It has long been observed that several flies (Simulium, Tabanus, ^ifa/.)and certain 

 other insects (Libellulidae, Ascalaphus, Ephemeridae, et al.)\\à\c two sizes of facets in each compound 

 eye; and that some have the field containing these differently sized facets well delimited, the fields being 

 in some cases actually separated from each other by a non-facetted line or b\- a constriction. When this 

 constriction is so complete that the eye is truh* divided, it may fairly be said that there are two pairs of 

 compound eyes, the two eyes of each lateral pair differing in the size of the facets. This last extreme 

 condition exists in the case of the males of certain Ephemerida; and in both males and females of Ble- 

 pharocera capitata. (And in almost all other Blepharocerid species.) 



» The eyes of Blepharocera are plainly divided; or it may be said that there are two on each 

 side (pi. I, f. 12). One of these eyes is dark-colored, has small facets, and faces ventrally, anteriorly and 

 laterally. It is fairly convex. The other is reddish brown, is composed of much larger facets, faces 

 dorsally, and has a nearly flat surface. This red, large-facetted dorsal eye has the appearance of a 

 flattened mushroom head, or thick plate, resting above the other eye. In the males, the dorsal, large- 



