Notes on Seasonal Dimorphism. 
417 
viz., (1) T, zde — T. hrigitta, (2j T. hiitleri = T. sethiopica, 
(3) T. floricola, (4) T. regularis = T. desjardinsii. 
The intimate relationship of T. zde to T. hrigitta has 
been remarked upon by Colonel Bowker, F.Z.S., etc., 
as far back as the year 1863, and in the April of that 
year he records the capture in Brit. Kaffraria oi $ T. zde 
in cop. with a $ T. hrigitta. During the changes of the 
season such instances of the copulation of the two 
forms are not infrequent, and I have noticed that 
generally the ^ or $ of the pair is of a slightly modified 
or transitional form of either T. zde or T. hrigitta. 
On the coast districts of Natal the true T. zde is only 
on the wing during the summer or wet season, and 
T. hrigitta during the late autumn and winter only. 
Numerous transitional or modified T. zde to T. hrigitta. 
forms keep up the sequence between them during the 
change of the seasons. 
The seasonal modification of T. zde to T. hrigitta is 
quite according to the rules upon which I lay so much 
stress, i.e., the attenuation of the black markings or 
borders of the upperside, and the adoption of a darker 
tint to the underside. 
T. hutleri is a rare form on the Natal coast, and 
T. dsthiopica by no means common. All my examples 
of T. hutleri have been caught during the summer 
months, and my T. sethiopica in the autumn or winter. 
The following are some dates of capture of T. hutleri 
and T. dsthiopica for the year 1889-90. 
jP. hutleri. 
Feb. 12th, 1889. 
Dec. 9th, 
Dec. 10th, „ 
Feb. 1st, 1890. 
March 31st, ,^ 
T. sethiopica. 
May 13th, 1889. 
June 4th, „ pr. mc^'p. 
April 24th, 1890. 
May 30th, „ 
July 1st, „ 
Judging by their general facies and the fact of their 
following one another seasonally, and that they comply 
with the same principles of modification, as cited in 
previous cases, I am strongly of the opinion that T. 
fethiopica is only the dry season variety of T. 
hutleri. 
Identically the same conditions point to the probability 
of T. desjardinsii being the dry season form of T. regu- 
