STUDY OF VARIATION IN THE RACES OF ZYGAENA F1LIPENDULAE, L. 129 



small as 27 mm., especially in the darker individuals. The latter are 

 also very blackish in tinge and with very little gloss. The sixth red 

 spot of forewing is only found in about 10% of the females and never 

 in the male. Only 6% of the males and 25% of the females in my 

 series can be described as having the hindwings red with a broad dark 

 margin and dark rays, 10% of the first and 25% of the second as 

 having them streaked with red and indigo in about equal proportions 

 of the two colours. Instead, as many as 40% of the males and 10% of 

 the females have the hindwings entirely black, with one red spot at 

 the end of cell ; the remainder are like these, but have some red rays 

 at the base, usually very thin ; in the females the spot is larger and 

 oblong and the rays are longer and thicker. One male and one 

 female out c.f about 200 specimens of this race I possess have no trace 

 of red left on hindwing (ab. niigrata, Dziurz). As a rule, however, the 

 five spots of forewing decrease in the same proportion as the single 

 spot of hindwing, and in culminating individuals, they are all reduced 

 to one or two dozen pinkish scales, scarcely visible to the naked eye in 

 extreme male examples ; these are small, frail, degenerate individuals, 

 with the dark scales of a dull black tinge, but, though they are nothing 

 but aberrations, they are produced comparatively often (roughly 

 1 : 100) ; the name of ab. parviguttata, Rocci (1914), can be used for 

 them ; a Tuscan specimen has been figured by Burgeff {Mitt. Mimchner 

 Ent. Ges., 1914, pi. III.), under the wrong name of nigratd, Dz. 

 My " typical " series is from Mount Prato Fiorito, collected from the 

 Fegana Valley, m. 600 to the top, m. 1000, above the Bagni di Lucca. 

 I have collected similar series at Piteglio, m. 700, above Pistoia. 



We have thus examined the series of gradually darkening races of 

 subspecies stoechadis from siciliemis and calabra to aterrima. 



According to their average size and following "the same order they 

 fall as follows in very natural groups and in successive grades in each 

 of these : 



Very small: montivaga, aterrima. 



Small : microcUsenheimeri ; medicaginis ; stoecliadis. 



Large : sicilieMis ; calabra ; major and oclisenheimeri ; pgrenes ; 

 duponcheli and etrusca ; uraria. 



Very large : gigantea. 



I have of course only mentioned the standard races, which have 

 been named. It must however, be noted that, owing to the consider- 

 able individual variation, especially in the darker races, we are obliged 

 to include, in each of these, series from various localities not exactly 

 similar to each other. It would, on the other hand, be quite unpractical 

 to multiply names on the ground of purely statistical data. To define 

 and convey more accurately the aspect of the various series, which may 

 be collected in different localities, I think the clearest and most 

 practical way is to establish and name a certain number of grades in 

 the line of individual variation, and to indicate the number of indi- 

 viduals which can be grouped in each of these. I will end this paper 

 with the following attempt to apply this method. 



By far the greatest amount of variation takes place on the hind- 

 wings and the general impression of greater or lesser development of 

 the primary dark pattern depends chiefly on their aspect. We must 

 therefore begin by working out these markings. 



(To be concluded.) 



