332 Prof. 0. Heer on the House Ant of Madeira. 



out two forms of labourers ; for example, in Formica herculeana, 

 L., and F. pubescens, F. ; only the difference is not so striking as 

 in the above-cited species. The same too with the Honey-bee ; 

 for in the same hive smaller and somewhat bigger labourers are 

 found, of which, according to Huber, the former take care of the 

 brood, the latter produce the wax. 



At present it is generally held, that the neuters found amongst 

 all these insects which live together in large families are im- 

 perfectly developed females ; and one would be led to this view 

 principally by the resemblance of the working-bees to the 

 females (the so-called queens), as well as by the fact, deduced 

 from certain experiments carried on with bees, that in many 

 cases they can make queens out of working-bees' eggs. When 

 indeed a comb full of eggs is introduced from another hive into 

 one without a queen, this last can sometimes rear itself a new 

 queen out of it ; but this by no means always happens, and I 

 have myself twice employed this method without any result, 

 which shows that queens cannot certainly be reared from all eggs 

 laid in the cells of working-bees. Amongst bees the labourer 

 indeed is very like the queen ; but with ants the difference 

 is very great : in these, not only are the females much larger 

 and winged, but they have an essentially differently formed 

 thorax; so that it seems quite incomprehensible to me that 

 merely the mode of nutriment should determine such different 

 kinds of individuals, and that it should depend on the labourers 

 whether a female or a labourer should proceed from the same egg. 

 But the explanation is rendered still more difficult by the occur- 

 rence of a second form of neuters, differing again as much from 

 the females as from the labourers. In this case we must therefore 

 hold, that ants possess the means of rearing labourers out of 

 some and soldiers out of other eggs, — which appears to us very 

 improbable. Hence we are almost compelled to ascribe the 

 distinction between the females, labourers, and soldiers, not to 

 the skill of the ants in rearing them, but to an original dif- 

 ference ; and consequently to admit, that not only in the male 

 and female individuals, but also in the labourers and soldiers, 

 the difference is congenital. This is borne out by the fact that 

 biformed individuals, between labourers and males (cf. Entomo- 

 logische Zeit. 1851, p. 295), have already been discovered, in 

 which one half exactly represents the male, the other half the 

 labourer; precisely like bisexual individuals in insects, between 

 male and female. Were the neuters undeveloped females, we 

 should not meet with forms like these, but we should rather have 

 forms of transition between neuters and females, which how- 

 ever is never the case. Against this view it may be alleged, 1 

 am well aware, that in the animal kingdom only two constantly 



