Bees carrying, or that have carried, Strepsiptera, are said to be stylopised (it being a species of the genus _Stylops_ that chiefly infests bees); the term is also used with a wider application, all Insects that carry a Strepsipterous parasite being termed stylopised, though it may be a Strepsipteron of a genus very different from _Stylops_ that attacks them. The development of one or more Strepsiptera in an Insect usually causes some deformity in the abdomen of its host, and effects considerable changes in the condition of its internal organs, and also in some of the external characters. Great difference of opinion prevails as to what these changes are; it is clear, however, that they vary much according to the species, and also according to the extent of the stylopisation. Usually only one _Stylops_ is developed in a bee; but two, three, and even four have been observed:[159] and in the case of the wasp, _Polistes_, Hubbard has observed that a single individual may bear eight or ten individuals of its Strepsipteron (_Xenos_, n. sp.?). [Illustration: Fig. 154—Young larva of _Stylops_ on a bee's-hair. Greatly magnified. (After Newport.)] There is no exact information as to how the young triungulins find their way to the bee-larvae they live in. Here again the discrepancy of opinion that prevails is probably due to great {301}difference really existing as to the method. When a _Stylops_ carried by an Insect (a Hymenopteron, be it noted, for we have no information whatever as to Hemiptera) produces young, they cover the body of the host as if it were powdered, being excessively minute and their numbers very great; many hundreds, if not thousands, of young being produced by a single _Stylops_. The species of the wasp genus _Polistes_ are specially subject to the attacks of _Stylops_; they are social Insects, and a stylopised specimen being sickly does not as a rule leave the nest; in this case the _Stylops_ larva may therefore have but little difficulty in finding its way to a Hymenopterous larva, for even though it may have to live for months before it has the chance of attaching itself to a nest-building female, yet it is clearly in the right neighbourhood. The bee genus _Andrena_ has, however, quite different habits; normally a single female makes her nest underground; but in the case of a stylopised female it is certain that no nest is built, and no larvae produced by a stylopised example, so that the young triungulins must leave the body of the bee in order to come near their prey. They can be active, and have great powers of leaping, so that it is perhaps in this way possible for them to attach themselves to a healthy female bee.