188 BRITISH LEPlt>OPTERA. 



yellow ; some were brownish-black, others of a beautiful chestnut • 

 brown, others yellowish - brown, dark clay -yellow or brownish- 

 red. Of 21 specimens, of which the ground-colours were noted, 

 9 were black, 9 clay -yellow and 3 brown, whilst each of the three 

 again showed various minor modifications of colour. The other 

 colours also varied somewhat. Thus, the " mirrors" were sometimes 

 white, sometimes strong yellow, and, occasionally, they also contained 

 a reddish nucleus. The variation in the shagreening was especially 

 interesting, inasmuch as these appeared to have a striking connection 

 with the general colouring of the larva. Black specimen's seldom 

 show such sparse shagreening as that represented in pi. v., fig. 

 46, but are generally thickly scattered with large shagreen-dots right 

 up to the dorsal line (pi. vi., fig. 4.7), these strikingly resembling the 

 adult larva of Hyles euphorbiae* '. The light ochreous-yellow individuals, 

 on the other hand, were sometimes entirely without shagreening (pi. 

 vi., fig. 48), being smooth and much resembling the light ochreous- 

 yellow or yellowish-red larva of H. nicaea (pi. vi., fig. 51). I have 

 never seen a larva of C. gallii which showed traces of the subdorsal 

 line in the last stage f, nor have I ever met one which possessed a 

 second row of "mirror" spots, so that retrogression or a sudden 

 advance in development does not appear to occur. The adult larva 

 of H. mauretanica, which likewise belongs to the gallii group, is very 

 similar to that of H. euphorbiae, but differs in the absence of the second 

 row of ring-spots. For this reason it must be regarded as a retarded 

 form at an older stage of phyletic development ( Weismann, Studies in 

 the Theory of Descent, pp. 213-2 15 \ 



Cocoon. — The larvae make for their puparium a rather coarse 

 network of threads, which binds the sand beneath them with the 

 Galium above into a slight cocoon ; those I had, had all retired by 

 October 8th (Buckler) ; the larvse spun up on the surface of the sand on 

 which the food was placed (Benthall) ; cocoons slight and spun on 

 the surface of the earth of the breeding-cage (Barnes) ; three or four 

 larvae (in confinement) pupated in the sand about an inch below the 

 surface, the remainder spun slight cocoons on the surface, mixing with 

 them portions of the food-plant, &c, and therein pupated (Newstead) ; 

 the larvae spin the leaves of the foodplant together, just under the sur- 

 face of the ground (Foster). Tugwell notes that several larvae that he 

 had in 1888 spun up just on the surface of the ground, but that the 

 greater number had simply formed a loose cocoon amongst the stems of 

 the foodplant, whilst six pupated from one to two inches beneath the 

 soil, and had formed fairly compact cocoons of silk and grains of sand. 



Pupa. — After a somewhat prolonged examination of the pupa in 

 comparison with that of Hyles euphorbiae, I find them to be extremely 

 alike, and that they differ only by one or two very trifling details. 

 [Whether a larger number of specimens than have been examined 

 would show these differences to be merely varietal and not specific, 

 or whether some more definite point of distinction would appear I 

 cannot, of course, say.] The sculpturing of the surface of both 

 consists of numbers of pits on the abdominal segments, these are alike 

 in both, in size and depth, and in a tendancy to lose their posterior 

 lips, and of the anterior lips to run together into a line ot arches. 



* See also Buckler's Larvae, &c., pi. xxiv., figs, if and if. In fact, the whole of 

 Buckler's figures on pi. xxiv illustrate this point excellently. 



f Buckler's pi. xxiv., lig. \c, gives some traces of this line. 



