FREE AMINO ACIDS IN INSECTS 123 
stances. The question is, however, whether differences in free amino acids do exist 
among different species. According to FLORKIN® the amino acid concentration in the 
gastropods is in general higher than that in the vertebrates, and that in the crustaceans 
still higher. Species-specific differences have been recorded in snails (KIRK, MAIN 
AND BEYER’; MICHEJDA AND URBANSKI!5; KIECOL AND MICHEJDA!®), Annelids 
(AucLAIR, HERLANT-MEEWIS AND DEMERS!) and in the eggs of various sea urchins 
(CHEN AND BALTZER®”; CHEN*?). According to DUCHATEAU et al.® the amino acid 
contents of Molluscs and Annelids are usually higher in the marine forms than in the 
related fresh-water forms. The same is true for crustaceans (CAMIEN et al.?8). As far as 
insects are concerned, DUCHATEAU AND FLORKIN®® estimated the free amino acid 
concentration in such specialized forms like Coleoptera, Hymenoptera and Lepidoptera 
to be at a higher level than that in the more primitive forms like Odonata and Orthop- 
tera. ROBERTSON?!” investigated the chromatographic patterns in 17 species belonging 
to Coleoptera, Lepidoptera, Diptera and Hymenoptera. Intergeneric differences were 
found for Laemophloeus, Acanthoscelides and Macrocentrus, and interspecific difference 
recorded for a variety of insects. Furthermore, two species of Laemophloeus differ in 
two reducing substances, probably amino sugars. Since the spots described by this 
authcr were separated only one-dimensionally and showed a number of overlappings, 
this work still has a preliminary character. 
Chromatographic patterns in various species of Hemiptera (7v1atoma gerstaeckert, 
T. infestans), Orthoptera (Periplaneta americana, Blatella germanica, Supella supel- 
lectilium) and Diptera (Culex molestus, C. fatigans, C. pipiens, Aedes aegypti, Anopheles 
quadrimaculatus ) have been compared in detail by Micxs?%’. In a later work similar 
analyses on 29 species of insects and ticks as well as geographic races from nine genera 
were carried out (Micks AND GiBson!). In general, different patterns between 
orders, species of the same genus, and even between races of the same species were 
noted. 
More extensive information is available for various mosquitoes. In an earlier paper 
CLARK AND Bat” stated the absence of tyrosine in Culex stigmatosoma, C. tarsalis 
and Culiseta incidens, but the presence of it in Aedes varipalpus. The presence of this 
amino acid was, however, detected in the Culex species in a later work of these two 
authors (CLARK AND BaLi4?; BALL AND CLARK"). Aspartic acid was recorded in C. 
tarsalis, C. quinquefasciatus, but not in C. stigmatosoma, A. varipalpus and Culiseta 
incidens. Furthermore, cysteic acid was absent in C. quinquefasciatus and Culiseta 
incidens, but present in the other species. Asparagine, phenylalanine and hydroxy- 
proline were consistently absent in all mosquito species examined by them. 
Micks AND Ettts!38 reported that the contents of free amino acids were in general 
at a high level in C. quinquefasciatus and A. aegypti. They also observed the absence 
of aspartic acid in A. aegypti, A. quadrimaculatus and C. salinarius. In order to detect 
differences between members of the pipiens-complex, MicKs!*6 performed both one- 
and two-dimensional chromatograms using C. pipiens, C. fatigans and C. molestus as 
testing materials. Two spots did not appear in the European species (C. pipiens) and 
one spot was absent in C. fatigans. Several quantitative differences were also noticed. 
Unfortunately, no identification of the spots was made, and the nature of these sub- 
stances is unknown. 
In an attempt to detect biochemical differences between different populations of 
the Anopheles maculipennis-complex LEWALLEN!” undertook chromatographic 
References p. 132/135 
