1913. j 149 



appearance and few in number that they give one the impression that 

 they would be very easily lost. Another distinction 1)eween liyhrida 

 and maritima lies in the comparative length of the hind tibise and 

 their tarsi ; in hybrida the hind tarsi are nearly as long as their tibise, 

 and in maritima distinctly shorter. This diiference is quite real, but 

 not very easy to appreciate, except in a series of carded specimens. 

 The variation of these two species in colour and band-form has been 

 the subject of much investigation on the part of Continental entomolo- 

 gists, and I am particularly indebted to Dr. Sharp for calling my 

 attention to a paper by Dr. von Lengerken (Berl. Ent. Zeitschr, 

 LVII, pp. 19-26), in which the matter is dealt with very fully. The 

 researches of Dr. von Lengerken lead him to arrange his material 

 according to the following table : — 



1. Wing-veins dark, not transparent. 



a. Median band hooked, the descending branch short or nearly horizontal. 



C. hyhrida hybrida, L. 



b. Median band formed as in maritima forma pseudo-maritima, Lengkn. 



2. Wing- veins clear, transparent. 



a. Median band hooked, bent at nearly a right angle... 



C. hybrida maritima, Latr. 

 h. Median band formed as in hybrida forma intermedia, Lengerkn. 



In our insects I find that the wing-characters employed by 

 )r. von Lengerken are correlated to the difference in the sctJpture 

 ' of the front part of the head, and the form of the aedeagus ; but, 

 whilst we have plenty of specimens in which the band-form is exactly 

 intermediate between hybrida and maritima, I have not yet seen any 

 example possessing the band-form which is regarded as distinctive of 

 hybrida, and at the same time the characters which I have given above 

 for maritima, or vice versa. For me, the most important specimens 

 mentioned by Dr. von Lengerken are the two pairs of maritima and 

 hybrida which he met with in copula. It would have been most 

 interesting to know whether the wing-characters were used as the 

 basis of determination of these specimens, and whether hybrida male 

 was paired with maritima female, or vice versa ; but I learn from 

 Dr. von Lengerken that these specimens cannot now be found. 



Colesborne, Cheltenham .- 

 April 7th, 1913. 



