pupae deaths were attributed to several parasites, including microsporidia, cytoplasmic and nuclear viruses, and larvae predation by birds, specifically identifying the common cuckoo (Cuculus canorus) and titmice. A more recent review, conducted in Spain, identified 17 species of parasites, viral diseases, unspecified predation and other, unknown, causes of death spanning from eggs not hatching, during summer, winter and spring as larvae, finishing with pupae failing to produce winged adults. Generally, mortality increased with population density, although in outbreak regions there was some compensation by females laying 21.6% more eggs (cause not discussed). Compsilura concinnata, a parasitic fly, pierces the brown-tail moth larva and deposits its own larva inside. This fly was introduced to North America in 1906 in an attempt to counter spongy moth, an invasive species. While not entirely successful for that purpose, one research group concluded that introduction of this fly had a great impact on brown-tail moths while not being as effective on spongy moths, the reason being that the fly larvae need to over-winter inside a host larvae. (Brown-tail moths over-winter as larvae, whereas spongy moths over-winter as eggs.) An older review describes other fly species that were confirmed as brown-tail moth larvae parasites, then released in U.S.: Apanteles lacteicolor, Metrous versicolor and Sturmia nidicola. Control Branch-tip webs can be clipped in winter and very early spring, and either dropped into a bucket of soapy water or burned. Gloves should be worn. Appropriate pesticides should be applied before early May because that is when the larvae start to develop harmful hairs. For organic garden and farm situations there are sprays that use a strain of Bacillus thuringiensis (Bt). Health issues Cicely Blair wrote a paper about the rash caused by the brown-tail moth caterpillar in the British Isles. It, and other descriptions, confirmed that loose hairs can break off and cause very itchy rashes on contact with skin, as well as breathing difficulties similar to asthma if inhaled. Rashes can persist for weeks. The same symptoms have been reported as far back as 1903. The reactions are due to a combination of mechanical and chemical stimuli, the barbed hairs in effect becoming lodged in and physically irritating the skin, and also functioning as microtubules to introduce irritating chemical compounds that have hydrolase, esterase and hemolytic activity. This rash reaction may be referred to as lepidopterism. The species should be handled using protective gloves at all stages