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.

    30/160 page 188
    ‘Chaetotaxy as follows: Head with frontal puncture slightly but distinctly nearer to frontal than to caudal clypeal seta ; puncture between setae i and ii nearer to seta ii ; seta vii (fig. 35) directly ventral to second ocellus. Prothorax (fig. 33) with dorsal - sclerite extending laterally to join spiracular sclerite on a broad front ; beta distinctly nearer to delta than to alpha, and gamma nearly twice as far from alpha as from epsilon. Pigroup of I bisetose with setae in a nearly horizontal line ; II-III unisetose ; 1-2 trisetose with nu antero-lateral to pi and slightly nearer pi than is tau which is nearly directly mesal to the latter ; 3-6 trisetose with nu directly anterior to pi and only about half as far from pias is tau ; 7 bisetose with nu nearly directly anterior and only slightly lateral to pi; 8 bisetose with nu anterior and only slightly mesal to pi ; 9 bisetose with nu antero-mesal to pi. Ninth abdominal segment with alpha between and anterior to beta and rho but nearer to the latter ; Kappa group with eta nearly directly anterior and only slightly dorsal to kappa, and mu nearly directly ventral to kappa and slightly further from the latter than is eta. Eta and kappa of 1-7 in an oblique line with eta antero-dorsal to kappa; 8 with eta and kappa in a nearly vertical line with kappa dorsal and only slightly caudal to eta. Epsilon of 1-8 minute, that of 8 being anterior to spiracle and separated from spiracle by a distance equal to about four or five diameters of the latter. Setae of I-III and 1-10 arising from pin- naculae except epsilon of 1-8 ; each pinnaculum is surrounded by a broad area, which is paler than adjacent parts of cuticle, and, if this area be considered part of pinnacu- lum, Kappa and Pi groups of the abdomen have their setae on the same pinnaculum. Ring around base of seta rho of II and 8 well sclerotised and very distinct. From all other members of the PHycITINAE dealt with here, it may be distinguished by having beta of the prothorax distinctly nearer to delta than to alpha. This is the only Pyralid known to me in which the pronotal sclerite is joined to the pre-spiracular sclerite along a broad front. Only a single blown specimen has been examined. Acrobasis juglandis (Le Baron) (Figs. 36-39). Mature Larva.—Length, 16-18 mm.; breadth, 2 mm. Cuticle dark greyish brown with a slight purplish tinge except as follows : most of head and mouth-parts, legs and crochets moderately dark red-brown ; meso-ventral margin of head black ; setae and sclerites of I and 10 yellowish brown ; peritreme. of spiracles very dark brown to black or nearly black ; and pinnaculae moderately pale grey or yellowish brown. Head (fig. 36) with front extending half way to vertical triangle and boundaries of adfrontals joining coronal suture at a point less than twice as far from vertical triangle as from front. Each side with six distinct ocelli (fig. 38) of which the second is slightly but distinctly nearer to third than to first. Mandible (fig. 37) with three distinct apical teeth. Maxillary mala with both ventral apical spines forked distally as shown in Acrobasis caryae (fig. 43). Spivacles of 8 round or very feebly obovate, about a fifth or sixth larger than membranous area enclosed by sclerotised ring around base of seta rho, and peritreme at most only feebly projecting and with caudal part, which is as thick as basal part of seta rho, slightly thicker than anterior part ; spiracles of 7 similar but only about two-thirds as large; spiracles of 1-6 similar to those of 7 but with those of 1 about a fifth larger ; spiracles of I larger than | those of 8 (4°8:3:5) and with outside diameter distinctly greater than distance between Kappa setae. Legs with front coxae separated by about a fifth of breadth of a front coxa; middle coxae about five and hind coxae about six or seven times as widely separated. Prolegs with crochets biordinal, the small crochets being about a third as long as large ones ; four anterior pairs of prolegs with crochets arranged in a complete circle. Chaetotaxy as follows : Head (fig. 36) with frontal puncture equidis- _ tant between caudal, clypeal and frontal seta ; puncture between setae i and ii slightly nearer i than il; seta vii (fig. 38) between and ventral to second and third ocelli. Prothorax (fig. 39) with beta slightly nearer to alpha than to delta, and gamma
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