FREE AMINO ACIDS IN INSECTS IIQ 
the absence of aspartic acid in C. salinarius (MICKS AND ELLIs?°8, 189), Analyses on 
protein hydrolyzates of the excreta of three mosquito species (A. aegyptr, C. pipiens, 
A. quadrimaculatus) revealed the presence of galactosamine and glucosamine in 
addition to 16 amino acids (IRREVERRE AND TERZIAN!?), 
In the larval blood of Calliphora erythrocephala FINLAYSON AND HAMMER® detected 
alanine, glycine, histidine, aspartic acid, lysine, isoleucine, leucine, phenylalanine, 
proline, tyrosine, serine and valine. Working on the same species AGRELL! reported 
in addition, glutamic acid, glutamine, /-alanine, methionine, taurine, threonine, two 
peptides and one hydrolysable substance in the body extracts of pupae. The latter 
author, however, did not mention histidine and phenylalanine. For Calliphora augur 
HackKmAN®*® observed four more amino acids: arginine, asparagine, hydroxyproline 
and cystine/cysteine. The concentration of these substances is apparently very low. 
In both larvae and adults of the house fly Musca domestica Pratt! identified at 
least 17 amino acids (Table I). Similar results have been reported recently by REIFF!*®. 
In the larval hemolymph of Corethra plumicornis CHEN AND HADORN*® observed at 
least 16 free amino acids and a peptide. The concentration of glutamine is particularly 
high in this insect, and proline seems to be absent in its blood. 
Coleoptera 
In the larval hemolymph of the mealworm Tenebrio molitor DRILHON®*® estimated 
seven amino acids, the relative concentration of which, beginning from the highest 
one, is as follows: serine, glycine, alanine, tyrosine, valine, proline, histidine. AUCLAIR 
AND DuBREUIL’, also by paper chromatography, included 11 more amino acids 
(Table I). The contents of lysine, alanine and tryptophane are especially low. In 
adult hemolymph of the Colorado beetle Leptinotarsa decemlineata SARLET et al.% 
reported 12 amino acids, among which glutamic acid and proline occur in strikingly 
high concentrations. The larval blood of this insect is especially rich in free amino acids. 
All together 21 ninhydrin-positive compounds including one unknown substance have 
been noted (AUCLAIR AND DUBREUIL®; DRILHON*®). 
Usstnc!6 reported the presence of lysine, arginine, histidine, tyrosine, leucine, 
valine, tryptophane and perhaps glutamine and hydroxyproline in the adult blood 
of the cockchafer Melolontha vulgaris and the wood-feeding beetle Ovyctes masicorms. 
Asparagine is found only in M. vulgaris. Hydroxyproline and four additional amino 
acids (glycine, serine, alanine, proline) were also detected in larvae of these two 
insects (DRILHON”®). 
Quantitative determinations of 14 amino acids in the adult hemolymph of the water 
beetle Hydrophilus piceus showed that glutamic acid and proline have by far the 
highest concentration (SARLET et al.'*!). As mentioned previously, glutamine was 
included in the glutamic acid data. While in the paper of SARLET ef al.'®! serine was 
not mentioned, DrILHON* reported its presence in this insect. In the hemolymph of 
the swimming beetle Dytiscus marginalis, FLORKIN AND DuCHATEAU® observed the 
occurrence of histidine and tyrosine, but the absence of arginine, tryptophane, phe- 
nylalanine and cystine. In a later work of DRILHON® the presence of valine, serine, 
leucine, glutamic acid, aspartic acid, tyrosine and histidine was identified. 
AUCLAIR AND DuBREUIL® established the amino acid composition of the larval 
blood of the Mexican bean beetle Epilachna varivestis (see Table 1). For Xylotrechus 
References p. 132/135 
