The Embryology of the Black Fly, Simulium Pictipes Hagen

Oviposition behaviour, egg-masses and hatching response of the eggs of five Nearctic species of Simulium (Diptera: Simuliidae)

“…Only those of S. (S.) parnassum Malloch have been reported to lack this triangular shape (Davies & Peterson, 1956). The prolarva is spirally coiled within the egg (Gambrell, 1933;Davis, 1971) so that the head fits into the anterior, most acute, angle of the egg (Hocking & Pickering, 1954). The sticky outermost covering of the egg is an exochorion composed of acidic mucopolysaccharides, is lamellar in structure and probably has a respiratory function (Williams, 1974).…”

“…The sticky outermost covering of the egg is an exochorion composed of acidic mucopolysaccharides, is lamellar in structure and probably has a respiratory function (Williams, 1974). The hardened shell is the chorion; it is tough, pigmented and quite impermeable to fixing fluids (Gambrell, 1933;Williams, 1974), although it remains translucent (Gambrell, 1933;Rubtsov, 1956). The prolarva is enclosed in a serosal cuticle (Williams, 1964).…”

Hox3/zen and the Evolution of Extraembryonic Epithelia in Insects

“…1). 14 However, it seems that in many lower dipterans the two mature epithelia fail to fuse again and persist or degenerate independently, while dorsal closure proceeds. [15][16][17] More radical departures from the ancestral trajectory have been reported for higher dipterans (Cyclorrhapha). Lower cyclorrhaphan flies such as the phorid fly Megaselia abdita or the syrphid fly Episyrphus balteatus initiate the formation of an amnioserosal fold, but while their serosa expands ventrally, their amnion disjoins from the leading edge of the serosa and grows over the dorsal side of the yolk sac (e.g., Megaselia, Fig.…”

Digestive system of larval black flies (Diptera: Simuliidae): structure and phylogeny

“…An internal esophageal invagination at the junction of the fore‐ and midgut is recessed into the midgut and reflected back on itself, forming a double layer, with epithelium and musculature sandwiched between cuticles (Crosskey 1990). The invagination forms within the first several days of embryological development (Gambrell 1933). The outer surface of the reflected cuticle bears flanges ( sensu Richards et al 1977) with posteriorly directed spines, first reported by van Gehuchten (1890) for the Nematocera and by Strickland (1913) and Puri (1925) for black flies.…”

“…Most gut characters in our study are drawn from the posterior portion of the foregut. The terminology for this portion of the foregut has been inconsistent in the Nematocera: esophageal fold (Strickland 1913), esophageal invagination (Clements 1963; Wigglesworth 1972), esophageal valve (Hallock 1922; Saunders 1924; Tanaka 1924, 1934; Puri 1925; Gambrell 1933; Comstock 1936; Crosskey 1990), proventriculus (Christophers 1960; Richards & Richards 1977; Richards & Seilheimer 1977; Richards et al 1977), and valvula cardiaca (Peters 1992). Wigglesworth (1930) used “proventriculus” as an inclusive term for the invaginated foregut and surrounding midgut.…”