The violin spider or black recluse spider is (presumably) a regional variant of the black widow found on the coastal region of Washington, USA and in parts of northernwestern Oregon, where true black widows aren't apparently able to survive for long periods of time.

Violin spiders are not commonly encountered, and due to the igorance of local fish and wildlife organizations, doctors and authorities often attribute bites to isolated incidents of non-native black widows or brown recluses being unwittingly brought in from other areas. This despite the fact that violin spiders inject a different type of venom than either the black widow or brown recluse (see below). Some people, having seen themselves bitten by this spider, have even been told by doctors that the bite was actually an allergic reaction to "bee sting", in spite of there being two small puncture wounds as seen on spider bites and the patient not necessarily being allergic to bee or wasp stings.

Likewise, the term "violin spider" is often (and incorrectly) assumed by both laymen and scientific ecological authorities to be a synonym for the brown recluse or "fiddle back" spider, probably because of the similarity in their names. Thus, many doctors and ecologists will erroneously claim that "violin spiders" do not exist in western Washington, referring to the brown recluse spider rather than the true violin spider.

As knowledge of this spider's existence remains rare in both the public mind and in scientific circles, its name is becoming increasingly misapplied to the brown recluse, and the existence of the true violin spider has become regarded as largely anecdotal and is wrongly regarded by many as an urban legend. For this reason, the violin spider may be regarded by some as a cryptid.

Appearance

Like most spiders, the violin spiders displays an extreme degree of sexual dimorphism. Morphologically, they are not even (externally) recognizable as members of the same species.

Unlike most spiders, the males and females are close in size. While for the most part the male is only about two thirds to three quarters the size of a female, an above average male can be noticeably larger than a below average female.

Female violin spider

She is nearly identical to the black widow, except that the marking on her abdomen has an irregular hourglass shape that generally resembles a violin, and can be either red, or more rarely, yellow, orange, or rust. She is often jet-black like the black widow, though she may instead be a swarthy (nearly-black) shade of brown, in which case the mark on her abdomen typically tends more toward the yellow, orange, or rust color than bright red. Female violin spiders also tend to be a bit smaller than true black widows.

Male violin spider

Male violin spiders strongly resemble the female fiddle back spider, but are somewhat smaller. They range from light tan to dark brown, often have a similar marking on their cephalothorax to that of the fiddle back, but generally have other markings on the tops of their abdomens as well.

Like most male spiders, their reproductive organs are on their mandibles, giving their mouthparts the distinctive "orb" shape.

Most males are on the lighter side of the species' pigment spectrum, most often light tan, and cases of albinism are plentiful.

Toxicity

Female violin spiders inject a powerful hemotoxin, unlike the black widow who possesses neurotoxin, or the fiddle back who possesses necrotoxin (see also biotoxin). It is unknown how potent her venom is, but multiple prolonged bites from a single spider can be fatal. However, she most often only injects a very small amount of venom -- enough to incapacitate small prey or cause slight swelling in humans. The bite of the female violin spider therefore rarely requires medical attention and often goes undiagnosed, if not unnoticed. Males are not venomous.

Behavior

To be written