424 LEPIDOPTERA CHAP. 



etc. ; others eat seeds, or dried vegetable substances. Three 

 out of our five British species of this family occur (usually 

 gregariously) in bee - hives, and have the peculiar habit 

 of spinning their cocoons together. The mass of common 

 cocoons formed in this manner by Aphomia sociella is remark- 

 ably tough and enduring ; portions of it are not infrequently 

 picked up, and as the cocoons are of a peculiar tubular form 

 their nature gives rise to some perplexity. 



Phycitidae * is another very large assemblage of Insects with 

 very diverse habits. The frenulum and retinaculum are similarly 

 formed in the two sexes : the males frequently have the basal-joint 

 of the antennae swollen ; hence the term " Knot-horns " applied 

 by collectors to these moths. The larvae of the species of 

 Ephestia infest groceries, and most children have become to a slight 

 extent acquainted with them amongst dried figs ; that of E. 

 kuehniella has become very injurious in flour-mills, its enormous 

 increase being due in all probability to the fact that the favour- 

 able and equable temperature maintained in the mills promotes a 

 rapid succession of generations, so that the Insect may increase 

 to such an extent as to entirely block the machinery. Many of 

 the Phycitidae feed on the bark of trees in galleries or tunnels 

 constructed partially of silk. A very peculiar modification of 

 this habit in Cecidipta excoecaria has been described by Berg. 2 

 In Argentina this Insect takes possession of the galls formed by 

 a Chermes on Excoecaria liglandulosa, a Euphorbiaceous tree. 

 The female moth lays an egg on a gall, and the resulting larva 

 bores into the gall and nourishes itself on the interior till all is 

 eaten except a thin external coat ; the caterpillar then pupates 

 in this chamber. The galls vary in size and shape, and the 

 larva displays much constructive ability in adapting its home to 

 its needs by the addition of tubes of silk or by other modes. Some- 

 times the amount of food furnished by the interior of the gall is 

 not sufficient ; the larva, in such cases, resorts to the leaves of the 

 plant for a supplement, but does not eat them in the usual 

 manner of a caterpillar; it cuts 'off and carries a leaf to the 

 entrance of its abode, fastens the leaf there with silk, and then 

 itself entering, feeds, from the interior, on the food it has thus 

 acquired. Another Phycitid, Dakruma coccidivora, is very 



1 Monograph, by Ragouot, in Romanoff', Mem. Lep. vii. 1893. 

 2 Ent. Zeit. Stettin, 1878, p. 230. 



