130 
LOEW AS A DIPTEEOLOGIST 
produce the corresponding passage: “ The species of Dasypogon 
which you left to my perspicacity to interpret 1 have subjected 
to a critical scrutiny. Dasypogon rufescens Macq. is very probably 
Diogmites discolor Loew; Macquart has overlooked the spurs on 
the front tibiae. Dasypogon falto Walk, is Cyrtopogon chrysopogon 
Loew; in Walker’s description you must read face instead of 
front. Dasypogon macerinus Walk., wretchedly described, seems to 
be your Anisopogon gibbus. Finally, Dasypogon lutatius Walk, is 
the species which, in my last invoice, I sent you under No. 458,” 
etc. This last species is introduced into my Catalogue of 1878, 
p. 69, as Cyrtopogon lutatius Walk. ; the other species will be 
found in their places as probable synonyms of Loew’s corre¬ 
sponding species. 
To the same wrong method of determining Diptera may be at¬ 
tributed Loew’s mistakes in the interpretation of generic descrip¬ 
tions. The genus Metoponia Macq., an Australian Chiromyzid, he 
identified with a North American Berid (compare above, p. 119) ; 
the North American Tipulid Cladura O. S. he wrongly recognized 
in a small European Limnophilid (compare my “ Studies on Tipu- 
lidaef Yol. II, p. 206 at top) ; Anarete Hal. lie mistook for a 
Cecidomyid (compare above, p. 115) ; his Chrysops gigantulus was 
in reality a Silvius (compare p. 120), etc. 
For a responsible entomologist it is quite indispensable to pos¬ 
sess this faculty of visualization, and it would be quite expedient, 
I think, to examine aspirants for appointments in museums in 
regard to it just as candidates for railway service are examined 
for color-vision. 1 
In my Chapter I, “On the Beginnings of my Relations with 
Loew,” etc., I have complained of my inability to come to an under¬ 
standing with him concerning the terminology of Diptera. When¬ 
ever I inquired about his views on the terminology of the venation, or 
of thesclerites of the thorax, I found him unprepared and hesitating, 
but profuse of promises. So, after much correspondence about 
venation , he wrote me (March 4, 1868): “ My work on venation 
you shall receive immediately, but I must first make a fair 
1 This account about “ the two methods of determining Diptera ” I have pub¬ 
lished in the Ent. Monthly Mag., London, December, 1901. 
