128 



KNOWLEDGE 



[July 1, 1892. 



of the danger to which they are exposed, must be greater 

 than in the case of the parasitic bees ah-eady referred to, 

 since not onlv is theirs the less venial offence, but if it 

 came to a fight, the Psithi/ri have their stings to defend 

 themselves with, and would no doubt give a tolerably good 

 account of themselves, while the flies have absolutely no 

 means of defence when once their disguise is penetrated, 

 and would be quite at the mercy of their foes. 



Volucella bomh/laiif does not confine its attentions to the 

 red-tailed bee, but visits the nests of the yellow-tailed ones 

 as well, and it is a remarkable fact that the colour of the 

 parasite varies with that of its host. Those individuals 

 that live with the red- tailed bee are themselves red-tailed, 

 but those that come from the nests of the yellow-tailed 

 ones themselves partake of this style of ornamentation, 

 and sliow no red at all ; so different in fact are these 

 varieties that it is difficult to believe that they represent 

 the same species. Other species of the same genus also 

 occur in bees' nests, but in these cases there is not the 

 resemblance between parasite and host that obtains in the 

 instance already cited, and yet the flies seem to be able to 

 elude observation and carry out their piratical enterprises 

 in safety and with success. These flies also inhabit wasps' 

 nests, where they destroy the brood ; in this case there is- 

 certaiuly no attempt to imitate the colours of the hosts, 

 but then, according to Sir .John Lubbock, wasps have the 

 colour sense less well developed than bees, and therefore 

 possibly any detailed imitation might only be thrown 

 away upon them. 



Another parasite to which some bumblebees are a prey, 

 is an insect not very commonly found in this country, and 

 sometimes called a solitary ant. Its scientific name is 

 Mntilhi Em-opcea (Fig. 2). It consists of males and females 

 only, the former of which are 

 winged as usual, but the latter 

 entirely apterous. The thorax is 

 bright red, and the abdomen, the 

 ground colour of which is black, 

 is prettily banded with thm lines 

 of glittering yellow hairs. Thus 

 it is quitt xmlike the bees in shape 

 and appearance, and the female 

 looks more like an extremely large 

 and very strong and stout ant. 

 This insect is carnivorous in its 

 habits, and its larvse devour those 

 of the bees, sometimes, in countries 

 where they are plentiful, destroy- 

 ing almost the whole brood ; in 

 this country they are never suffi- 

 ciently numerous to do this. That 

 they are neither essential parasites of the Bomhi, nor entirely 

 confined to those insects is clear from the facts that though 

 the Bomhi are extremely common insects with us, the Mutilla; 

 are rather rare, and there must be hundreds of nests of bees 

 from which they are absent, and that, on the other hand, 

 Mutillii either of this species or others closely allied a,re 

 often abundant in countries where Bombiiii is either rare 

 or does not exist at all. Other insects also may be found 

 in the nests of social bees, such as little beetles and mites. 

 The former come in fcr the sake of the wax, with which 

 the honey-pots of the bees are made, and the latter partly 

 for this too, but also to attack the bees themselves, to 

 whose bodies they cling, and whose juices they suck, 

 exhibiting thus a third type of parasitism. In the other 

 instances we had the parasites attacking either the food of 

 the young bees, or the larvae themselves ; now we have 

 parasites which subsist upon the perfect insects. 

 (To be continued.) 



THE DISTRIBUTION OF SUNSPOTS IN SOLAR 

 LATITUDE. 



By E. W. Maunder, F.R.A.S., 



Assistant superintending tJie Solar and Spectroscopic Depart- 

 ments at thf Eoyal Ohservator;/, Greenwich. 



TO the attentive observer of solar phenomena, the 

 vast size, beautiful detail, and changes of form of 

 the great group of February last did not constitute 

 its only, perhaps not its chief claim to notice ; 

 and even its association with the great magnetic 

 storm of February 12th, and with the appearance of 

 auroriB, is scarcely of more importance than the featm'e to 

 which I wish now to allude — I mean its drift in solar 

 latitude. 



FlG.2. — MiifillaEuropcea, 

 a parasite of tumble 

 bees, magnified three 

 diameters. 



Just before Miniunuu. 



Briefly the history of this great outburst is as follows : 

 A considerable group was observed in S. lat. 19"^ during 

 November, 1891, and it was accompanied by two com- 

 panion groups, which for the sake of distinction we will 

 call B and C, denominating the principal group as A. B 

 was in S. lat. 19\ and C in S. lat. 11 '. During December 

 C was not observed, but A and B were ; the former in 

 S. lat. 20^ the latter in S. lat. 19°. During this rotation 

 B became the more considerable group, and in the next 



fter Minimum. 



rotation, that of January, 1892, it was seen alone ; this 

 time in S. lat. 2.5°. During February, when it attained its 

 greatest development, its latitude was 27-5°, and in 

 March, when it was much smaller in area, it was a little 



