Article beginning on page 67.
Psyche 6:67, 1891.

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April 1891.1
PSYCHE.
Halobates. The insect, of which Dr. Lion had only a single specimen, is 4 mm. long. Its mouth "is constructed exactly like that of the Hemiptera," it has typical hemipteran antennae, a pair of prominent compound
eyes, three stemmata, and the head is not freely attached to the thorax. The wings, of which only the mesothoracic pair is present, appear to be hyaline, with a venation which by no stretch of the imagination can be regarded as dipteran. The legs are hairy and adap- ted to swimming; there are three tarsal
joints, the last of which terminates in a sin- gle claw. When we come to look for dipte- ran characters the only one that can be found is the lack of metathoracic wings ; as if this character were sufficient to elevate a hemip- ter to the rank of a diptw! Has Dr. Lion ever heard of the two-winged male Coccidae, which no tyro in entomology would think of placing among the Diptera? The stemmata
furnish Dr. Lion with another reason for re- garding his insect as allied to the Diptera, because, forsooth, the Hydrocorisa have no steminata! We are informed that at the
very beginning of his examination of this insect, Dr. Lion saw that he was not dealing with a Halobates but with a form which re- sembles a dipter more than a hemipter. He further states that Dr. Arnold Lang, to whom he communicated his observations was of the same opinion. We cannot believe that so
eminent a phylogenist as Dr. Lang could
have examined the specimen. The insect is not a hemidipter but a genuine hemipter
albeit with only one pair of wings. It will hardly be necessary to study its ontogeny for the sake of ascertaining that it does not hatch as a maggot and does not pass through a quiescent pupa stage. W. M. WHEELER.
-
PROTECTION BY CONSPICUOUS COLORS.-
The following passages in Lord Walsing-
ham's last presidential address to the Ento- mological society of London are sugges-
tive :-
'My attention was lately drawn to a pas- sage in Herbert Spencer's 'Essay on the
Morals of Trade.' He writes :-'As when
tasting different foods or wines the palate is disabled by something strongly flavoured from appreciating the more delicate flavour of another thing afterwards taken, so with the other organs of sense, a temporary disability follows an excessive stimulation. This holds not only with-the eyes in judging of colours, but also with the fingers in judging of tex- tures. ' "
"Here, I think, we have an explanation of the principle on which protection is undoubt- edly afforded to certain insects by the pos- session of bright colouring on such parts of their wings or bodies as can be instantly cov- ered and concealed at will. It is an un- doubted fact, and one which must have been observed by nearly all collectors of insects abroad, and perhaps also in our own country, that it is more easy to follow with the eye the rapid movements of a more conspicuous insect soberly and uniformly coloured than those of an insect capable of changing in an instant the appearance it presents. The eye, having once fixed itself upon an object of a certain form and colour, conveys to the mind a corresponding impression, and if that im- pression is suddenly found to be unreliable the instruction which the mind conveys to the eye becomes also unreliable, and the ra- pidity with which the impression and conse- quent instruction can be changed will not always compete successfully with the rapid transformation effected by the insect in its efforts toescape. . . .
"If this protective effect of the partial and intermittent display of brilliant colouring is so obvious in relation to the human eye, must it not be at least equally so in relation to the eyes of its more natural enemies, such as birds, and have we not here indicated a new and distinct line of investigation as re- gards the use and advantage of brilliant colours in many cases which cannot be ac- counted for by the theory that they are de- veloped for the purpose of warning, or
through their aesthetic relation to court- ship ?"




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