524 BRITISH LEPIDOPTERA. 



basal line, and apparently with a common ochreous aberration. The 

 Japanese M. testacea is by common consent now considered to be 

 specifically identical with M. neustria. 



Having already noted the chief points of difference between 2[. 

 castrensis and the allied 21. alpicola and M. franconica, we may now 

 mention the hybrids that Standfuss has obtained between the three 

 species, castrensis, franconica, and neustria. A pair of the crosses 

 between franconica and castrensis are in the British Museum coll. The 

 $ shows in the deepening ground colour, the darker nervures, the 

 direction of the transverse lines, and in the thinning of the scaling in the 

 median areas of the wings, an approach to franconica. On the other 

 hand, the distinctly denser scaling (compared with franconica) is 

 unquestionably derived from castrensis. The female also exhibits distinct 

 intermediate characters — the large more elongated forewings and the 

 smooth unicolorous appearance of the wings suggest franconica, whilst 

 the barely traceable central band and the dense scaling are indicative of 

 castrensis. Standfuss' interesting account of breeding these and other 

 hybrids reads (Stett. Ent. Zeit., xlv., pp. 193, 194) as follows : — 



(1) Malacosoma neustria $ and franconica J . — In the Eoman 

 Campagna larvae of 21. franconica are exceedingly common. In 1884, 

 from June 10th onwards, many females of this species emerged, and as 

 21. neustria males were coming in hundreds to light, endeavours to 

 pair the two species were made and were successful in a number of 

 cases. Copulation lasted at most from 5-15 minutes, and the females 

 immediately sought with the ovipositor a suitable place on a dry twig 

 on which to oviposit. Thus far all the females acted similarly, but 

 then differences occurred. Four fertilised females, having apparently 

 obtained a good position, vainly endeavoured to deposit their eggs, and 

 fell to the ground without laying a single one, and died in from three 

 to four hours ; it was assumed, as this never happened when the 2 of 

 franconica was very large, or the $ of neustria very small, that this 

 was due to the unsuitability of the organs of copulation and that the 

 $ sexual organ of neustria was ordinarily too long. In other cases 

 the fertilised females laid all their eggs quite normally, properly 

 arranged. An intermediate condition was noticed in some instances, 

 viz., that the female, after copulation, laid no eggs or at most 6-12, 

 then left the twig and commenced to " call " again vigorously ; after 

 copulating a second time the ? then laid, so far as could be judged, 

 all her eggs. The eggs laid by these females (whether paired once or 

 twice) were all fertile, as proved by an examination in September, 

 when they were found to contain living larvae. It appears as if these 

 species cannot lay infertile eggs. Five batches of from 400-600 eggs 

 each were laid. Of these, in spite of the eggs containing living larvae 

 in September, the following numbers only hatched — 0, 15, 23, 65, 151. 

 Most of the larvae failed to escape from the egg-shells, and even of 

 those that did, several died without even commencing to feed. Only a 

 dozen larvae reached full-growth, but these all produced well-developed 

 moths. The larvae varied remarkably, and represented almost all 

 transitions from neustria to franconica, yet the imagines are all 

 essentially alike. 



a. hybr. caradjae, Stdfss., "Handbuch, &c," p. 62, pi. iii., fig. 3 (1896).— Wing 

 expanse 26mm.-28ram., intermediate between neustria and franconica. Tbe fore- 

 wings dark brown throughout except that the median band is bordered oa both sides 



