158 Mr. W. S. MacLeay on tlie Anatomy of the 



and a body consisting of twelve segments. It follows of course that the 

 first pair of feet, as they are called in all octopod Arachnida, whether 

 spideis, scorpions or mites, are nothing else than the labial palpi oi 

 winged insects.* This is, it is true, a novel mode of viewing Crustacea 

 and Arachnida, but as it leads to some most curious results, I shall prove 

 its accuracy at a future opportunity, and shew in what the variations from 

 this type really consist. My business at present must be with winged in- 

 sects, in which the same rule not only holds good but is typical. 



Let us observe a Phasma, where the female is apterous and the male 

 winged. In many females of this genus we may perceive the rudiments 

 of the wings, and consequently the inspection of a female will point out 

 to us the structure of the male, considering this last as a perfect winged 

 insect. Well then the female Phasma shews nine abdominal segments, 

 three thoracic and a head. The females of certain Blattee are apterous, 

 and in the island of Cuba there is a large insect of this genus to be found 

 under stones in woods, whose four wings are formed, but so sliort and 

 truncated as to render the possessor incapable of flight. Such insects 

 will also prove a winged Blatta to be composed of the abovementioned 

 thirteen segments. The same results are derived from the examination 

 of the larvae and females of Drilus and Lampyris. It is true that some 

 of the abdominal segments become more or less confluent in certain in- 



* A careful study of the very curious and distinct order oi Arachnida, and 

 in particular of the genera Mygale, Scorpio, Pliryne, Galeodes, Gonyleptes, 

 and Chelifer, in a live state, has convinced me that M. Latreille's idea of these 

 insects being supplied with antennae is correct. Another certain character of 

 the class is to have the labial palpi converted into a pair of feet which are ge- 

 nerally of the same form as the six true feet. Mr. Kirby's ingenuity detected 

 (see Int. to Ent. Vol. IV., p. 387.) what are commonly called the first pair of 

 feet in Scorpions and Spiders, to represent the palpi of winged insects ; but he 

 appears to consider them as the maxillary palpi, whereas they in reality repre- 

 sent the labial. A still greater mistake, indeed an unaccountable one in a per- 

 son of his science, has been his not perceiving that the same rule holds good 

 in the Acaridm, and his placing these most evident Arachnida with hexapod 

 Ametabola, to which they have no earthly relation, unless perhaps it be that of 

 a slight, and a very slight, affinity of transultation. 



