Insect pests of food.

  • Great Britain. Ministry of Food.
Date:
1943]
Catalogue details

Licence: Public Domain Mark

Credit: Insect pests of food. Source: Wellcome Collection.

    22/160 (page 180)
    margin broadly and moderately deeply sinuate at apical third. Spiracles of 8 (fig. 18) obovate with vertical diameter much greater than horizontal, nearly twice as large as those of 7 (7:5: 4-0), and with caudal part of peritreme distinctly thicker than anterior part; spiracles of 1-7 similar to those of 8 but much smaller and with caudal part of peritreme one and a half to twice as thick as anterior part, those of 1 and 7 being very slightly larger than those of 2-6; spiracles of I smaller than those of 8 (5:5: 7:5) and with peritreme thickened as in those of 1-7. Legs with front coxae separated by a sixth or seventh of breadth of a front coxa ; middle coxae four times and hind coxae five times as widely separated. Prolegs with small crochets only a third to a half as long as large crochets ; four anterior pairs of prolegs with crochets . arranged in a complete circle. Chaetotaxy (figs. 17-18) as follows : Head (fig. 17) with frontal puncture nearly as caudal as frontal seta and much nearer to the latter than to caudal clypeal seta ; seta i twice as far as seta ii from puncture normally between them and 1 almost directly lateral to ii. Pi group of I-III bisetose with setae in a nearly - horizontal line, but with anterior seta slightly more ventral than caudal seta; 1-2. trisetose with pi and tau in a transverse line, nu being anterior to both ; 3-6 trisetose with nu antero-lateral to pi and about as far from pi as is tau so that lines joining them would form a nearly equilateral triangle ; 7-8 bisetose with nu anterior and slightly lateral to pi; 9 unisetose. Ninth abdominal segment with alpha between and anterior to beta and rho and slightly nearer to rho than to beta ; Kappa group with eta dorsal and slightly anterior to kappa and about a third as far from kappa as is eta, which is nearly directly ventral to kappa. . Eta and kappa of 1-8 (fig. 18) in a vertical line, eta being directly dorsal to kappa. Dorsal setae of 1-8 without pin- naculae ; sclerotised ring around base of seta rho of 1 and 8 often very indistinct, that of 1 being frequently absent, in which case the pigmented bar is sometimes scarcely visible. . Earlier Instars.—The smallest available larva is 6 mm. long, and it is identical in structure with the mature larva. This species and Galleria mellonella (L.) are, as far as I am aware, the only two species of the subfamily GALLERIINAE that have the Pi and group of the meso- and metathorax bisetose instead of unisetose. Both species inhabit beehives, and the ocelli are reduced in number or absent. Of the two species, the blind A. grisella appears to be the more specialised for life inside hives. A. grisella may be distinguished from G. mellonella as follows: (1) mature larvae with body shorter and relatively more slender; (2) non-sclerotised parts of cuticle of thorax and abdomen with asperities very indistinct and of same colour as cuticle between them instead of being much darker; .(3) head without ocelli instead of having four on each side; (4) mandible (fig. 15) with outer ventral margin broadly and moderately deeply sinuate at apical third; (5) peritreme of spiracles black or nearly so and with caudal part (at least of I and 1-7) distinctly thicker than anterior part, whereas in 6. mellonella the peritreme is moderately pale brown and evenly thickened; (6) front coxae » separated by a sixth or seventh of breadth of a front coxa instead of by about a half of breadth of coxa; (7) prolegs with small crochets one-third to one-half instead of two-thirds to four-fifths as long as large crochets ; (8) seta 11 of head much nearer to puncture normally between i and ii than is i which is nearly directly lateral to it ; (9) Kappa setae of prothorax in a line opposite ventral instead of dorsal margin of spiracle ; (10) eta and kappa of 1-8 (fig. 18) in a vertical instead of an oblique or nearly horizontal line ; and (11) Pi group of 7 with nu nearly directly anterior instead of nearly directly lateral to pi. Aphomia sociella (L.). (Figs. 19-22). Mature Larva.—Length, 22-27 mm.; breadth, 3-4 mm. Cuticle pale yellow except as follows : most of head and pronotal sclerite pale yellowish-brown ; anterior part of head, meso-ventral margin opposite stipes and cardo, and apices of mandibles